A grim discovery in a Swedish lake reveals ancient practices; in the Canadian Arctic, the fossil of a previously unknown mammal is found; bizarre ice formations in the Antarctic Ocean; a discovery off the east coast of Canada.

In the remote Cagayan Valley of the Philippines, archaeologists discover the remains of an ancient rhinoceros; a Brazilian island is infested with thousands of deadly vipers; researchers uncover shocking human remains deep in a Kenyan cave.

A special episode featuring a compilation of games, moments and outtakes of never-before-seen footage.

Improv veterans Ryan Stiles, Wayne Brady and Colin Mochrie return for a new take on the comedy series with host, Aisha Tyler. Each episode, a special guest star joins the comics as they tackle a series of spontaneous improvised sketches, with only a few random ideas from the studio audience and their host. With little information and a lot of imagination, the comics depict a variety of characters and scenes, and even perform songs. At the end of each round, Aisha awards points to each of the four performers and announces a winner at the end of every episode.

A deadly volcano eruption causes catastrophic destruction, and a tornado flips cars on a highway.

Seeing the home of a hush-hush Alabama fraternal organization that changed America and a testament to Allied heroism in North America; looking around a once lavish Beirut complex scarred by tragedy; visiting an elite leadership centre in Greece.

The Dendera Temple is one of the best-preserved temples in all of Egypt; experts decipher its mystifying zodiac images and uncover the ceremonial events that took place at this sacred site, and stunning CGI rebuilds this grand complex in its prime.

Confronting an aggressive, barn-size UFO and a bizarre whistling flying saucer.

On New Year's Eve, Texans report a series of flashing lights falling from the heavens; investigating an alien craft that allegedly cured a French doctor's injury without ever touching him.

Budding entrepreneurs get three minutes to pitch their business ideas to five multimillionaires who are willing to invest their own cash to kick-start the businesses in the original "Shark Tank." After each pitch, the Dragons have the opportunity to ask questions about the venture. The entrepreneurs don't always have to answer, but of course what they choose not to address could very well affect the outcome. The pitch is over when each of the Dragons has declared,"I'm out." Evan Davis hosts.

Billy Meier claims he's traveled through time and space with an alien race from the Pleiades star cluster; in the decades following his revelation, both skeptics and ufologists say it's a hoax despite Meier providing photographic evidence.

Confront objects that make no sense; spot a spinning island in an Argentinian marsh, a colossal triangle stuck in the Arizona desert, mysterious multicoloured pools across northern Ethiopia and a huge human figure hidden in the Australian outback.

Preserved in the ice of Mexico's highest peak, a group of climbers stumble upon the bizarre, mummified remains of a man in a pinstripe business suit; experts uncover possible drug cartel connections and a plane crash shrouded in secrecy.

The last remaining fugitives must reach a pre-arranged extraction point to evade capture; with seven days to go, the hunters ramp up their efforts.

Contestants compete across the series, scoring points by answering questions correctly; they must avoid the impossible answers, otherwise they will be eliminated until the next day.

Wayne Brady, Ryan Stiles Colin Mochrie and guest performer Greg Proops are joined by star guest Kat Graham to put their comedic skills to the test through a series of spontaneous improv games.

A special episode featuring a compilation of games, moments, and outtakes of never-before-seen footage.

Exploring the drug-war front lines in Panama and an Alpine utopia with a dark past; visiting Poland for a peek inside a revolutionary prison; getting close to a Tunisian monument.

Visit Cambodia, where record droughts have left a trade hub exposed; examine a submerged funerary complex in Greece, ancient mammal footprints preserved by a Turkish volcanic eruption and North American fossils from the post-dinosaur era.

Flash floods tear through Maryland in the US, a couple get stranded in a Himalayan blizzard, and a boat race is besieged by a rare weather phenomenon.

Preserved in the ice of Mexico's highest peak, a group of climbers stumble upon the bizarre, mummified remains of a man in a pinstripe business suit; experts uncover possible drug cartel connections and a plane crash shrouded in secrecy.

Visit Cambodia, where record droughts have left a trade hub exposed; examine a submerged funerary complex in Greece, ancient mammal footprints preserved by a Turkish volcanic eruption and North American fossils from the post-dinosaur era.

Flash floods tear through Maryland in the US, a couple get stranded in a Himalayan blizzard, and a boat race is besieged by a rare weather phenomenon.

Confront objects that make no sense; spot a spinning island in an Argentinian marsh, a colossal triangle stuck in the Arizona desert, mysterious multicoloured pools across northern Ethiopia and a huge human figure hidden in the Australian outback.

Glen Powell in dystopian action thriller "The Running Man"; Brit Rosamund Pike in "Now You See Me: Now You Don't"; Jack Whitehall, starring in "Malice"; and Ed Sheeran, who performs from his album "Play.".

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

A compilation of games, moments, and outtakes of never-before-seen footage.

A special episode featuring a compilation of games, moments and outtakes of never-before-seen footage.

Glen Powell in dystopian action thriller "The Running Man"; Brit Rosamund Pike in "Now You See Me: Now You Don't"; Jack Whitehall, starring in "Malice"; and Ed Sheeran, who performs from his album "Play.".

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

Contestants compete across the series, scoring points by answering questions correctly; they must avoid the impossible answers, otherwise they will be eliminated until the next day.

Flash floods tear through Maryland in the US, a couple get stranded in a Himalayan blizzard, and a boat race is besieged by a rare weather phenomenon.

Exploring the drug-war front lines in Panama and an Alpine utopia with a dark past; visiting Poland for a peek inside a revolutionary prison; getting close to a Tunisian monument.

Archaeologists find a tomb, a haunting cave, and a sophisticated labyrinth.

In the Arctic Circle eerie multicolored lights move across the night sky, highway streetlights inexplicably start swaying wildly, threatening motorists and a perfectly circular beach and ocean appear in dense forest.

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

Watching "The Inheritance," "Long Lost Family," "Unknown Number: The High School Catfish," "The Yorkshire Vet," "Dish It Out" and "Street Cops: Catching the Troublemakers.".

Weighing options carefully as Rick welcomes 24 new contestants, who all want a chance to make 10,000 one-pound coins rain from the giant exclamation point on stage; seeing who wins big by keeping their cool and dodging the impossible answers.

Players who think they know how to unlock a big payout.

The first sightings of the UFO flap in Piedmont, Mo. are reported; Over 500 reports are made in the following months; A family driving to Ontario encounters mysterious lights and a cigar-shaped craft.

Paid programming.

Weighing options carefully as Rick welcomes 24 new contestants, who all want a chance to make 10,000 one-pound coins rain from the giant exclamation point on stage; seeing who wins big by keeping their cool and dodging the impossible answers.

The West Coast is home to the San Andreas fault, stretching for almost a thousand miles beneath the feet of millions of Americans.

Hurricanes, droughts and storms reveal strange mysteries, relics and artifacts.

The failed controlled demolition of The Clarion hotel in Las Vegas; substandard soil conditions and reclaimed land are among the reasons for construction site collapses; how construction, urbanization and heavy equipment contribute to sinkholes.

Fails include an overpass fire, a downed radio telescope and a sinking airport.

Fails include a disastrous shuttle mission, and an unwanted and very expensive airport.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

Ross Noble, Sara Pascoe and Sally Phillips join Sandi and Alan for a varied episode.

Aisling Bea, Mark Watson and Michelle Wolf join Sandi Toksvig and Alan Davis for a volatile episode.

Archaeologists find a tomb, a haunting cave, and a sophisticated labyrinth.

The failed controlled demolition of The Clarion hotel in Las Vegas; substandard soil conditions and reclaimed land are among the reasons for construction site collapses; how construction, urbanization and heavy equipment contribute to sinkholes.

Fails include an overpass fire, a downed radio telescope and a sinking airport.

Fails include a disastrous shuttle mission, and an unwanted and very expensive airport.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

A thousand-year-old Italian tower is brought to the brink of collapse; a Viking stronghold in Greenland, inexplicably abandoned; the ghost WWII bomber that vanishes on its return to base.

Unable to accept the fact that her daughter is dying, Rose (Radha Mitchell) decides to take the girl to a faith healer. On the way, the pair drive through a portal in reality, leading to an eerie town called Silent Hill. The town is surrounded by a potent darkness, and the human survivors fight a losing battle against it.

Confronting an aggressive, barn-size UFO and a bizarre whistling flying saucer.

Hurricanes, droughts and storms reveal strange mysteries, relics and artifacts.

Three men vanish from a remote Scottish lighthouse; dozens of mines explode simultaneously during the Vietnam War, for no apparent reason; ten billion snow crabs disappear from the Bering Sea.

The investigation of some of the most notorious and mysterious events, in an attempt to unravel all the possible reasons for the disasters.

The investigation of some of the most notorious and mysterious events, in an attempt to unravel all the possible reasons for the disasters.

The West Coast is home to the San Andreas fault, stretching for almost a thousand miles beneath the feet of millions of Americans.

Earthquakes, droughts and collapsing dams expose artifacts and graves.

Cousins Billy and John Smith encounter a massive ship triple the size of a football stadium; guards at Malmstrom Air Force Base in Montana spot an unidentified object overhead.

Paid programming.

Players who think they know how to unlock a big payout.

Squaring off on national parks, Downton Abbey, musical theatre and human anatomy.

Zoom in on some otherworldly sights; spot a giant glacier on the Red Planet, let the milky seas off the coast of Java bathe your vision, ponder a huge hexagon floating above Saturn and take a spin around a doughnut-shaped lake in Saskatchewan.

Explores strongholds abandoned by their architects; a lost city in the Amazon jungle; a desert fortress made by humanity's most notorious empire; explores a city of identical castles; examines a Greek isle's bloody history from the air.

Explorers discover tunnel systems, a sprawling city, and military barracks.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

Explorers find a tunnel system, mass graves, city foundations, and longhouses.

The last remaining fugitives must reach a pre-arranged extraction point to evade capture; with seven days to go, the hunters ramp up their efforts.

A dilapidated mansion in Virginia, raided during the Civil War; the nerve center of a heroic rescue mission in England; palatial ruins in Estonia that hosted a formidable empress; and a fitness facility in Detroit where a champion made his name.

Board a WW II aircraft carrier and find out why a ghost orb flew through the captain's office. Tour the huge ship to learn about sailors who tragically died in battle, then watch Jennifer's team try to make contact with spirits in the engine room.

Confront objects that make no sense; spot a spinning island in an Argentinian marsh, a colossal triangle stuck in the Arizona desert, mysterious multicoloured pools across northern Ethiopia and a huge human figure hidden in the Australian outback.

A dilapidated mansion in Virginia, raided during the Civil War; the nerve center of a heroic rescue mission in England; palatial ruins in Estonia that hosted a formidable empress; and a fitness facility in Detroit where a champion made his name.

Zoom in on some otherworldly sights; spot a giant glacier on the Red Planet, let the milky seas off the coast of Java bathe your vision, ponder a huge hexagon floating above Saturn and take a spin around a doughnut-shaped lake in Saskatchewan.

Explores strongholds abandoned by their architects; a lost city in the Amazon jungle; a desert fortress made by humanity's most notorious empire; explores a city of identical castles; examines a Greek isle's bloody history from the air.

Peek at landmarks in places where they shouldn't be; wing your way over an imperial pyramid in the Netherlands, a metal sphere in remote Russia, a lion shape carved into an English hillside and a bare swath cut through an Austrian forest.

Explorers find a tunnel system, mass graves, city foundations, and longhouses.

Earthquakes, droughts and collapsing dams expose artifacts and graves.

A thousand-year-old Italian tower is brought to the brink of collapse; a Viking stronghold in Greenland, inexplicably abandoned; the ghost WWII bomber that vanishes on its return to base.

Scientists uncover a city, a chamber, and a complex, and map a tunnel network.

Scientists uncover salt chambers, bunkers, old kingdoms, and mysterious caves.

Contractor Mike Holmes joins forces with his children, Michael and Sherry, to continue his legacy of making it right and helping homeowners in need.

The failed controlled demolition of The Clarion hotel in Las Vegas; substandard soil conditions and reclaimed land are among the reasons for construction site collapses; how construction, urbanization and heavy equipment contribute to sinkholes.

Three men vanish from a remote Scottish lighthouse; dozens of mines explode simultaneously during the Vietnam War, for no apparent reason; ten billion snow crabs disappear from the Bering Sea.

The investigation of some of the most notorious and mysterious events, in an attempt to unravel all the possible reasons for the disasters.

New York City is under attack as Hurricanes Ida and Ian unleash their fury on innocent people; seeing how the latest science and technology can protect New York City's 8 million residents before everything gets swept away by ferocious superstorms.

New York City is under attack as Hurricanes Ida and Ian unleash their fury on innocent people; seeing how the latest science and technology can protect New York City's 8 million residents before everything gets swept away by ferocious superstorms.

Encounter kids' drawings on the walls in Pompeii that expose the city's violent gladiatorial past; check out a mythical sculpture unearthed by an Indian tsunami, a 12-century temple in quake-prone Mexico; a sunken ship in Utah's Great Salt Lake.

Contractor Mike Holmes joins forces with his children, Michael and Sherry, to continue his legacy of making it right and helping homeowners in need.

The Holmes team surprises superfan Michael, who has autism, with news that he's part of the crew; his family gets a life-changing upgrade that will open up their tired bungalow and give them more room for living.

Dealing with toxic fallout after a hot real estate market forces Jason and Alisha to buy a house without getting a home inspection; the Holmes team transforms a moldy, radon-filled eyesore into a cozy, healthy place to raise a family.

A buried ship, wartime cellars, jar burials and mass graves are excavated.

Take a deep dive into watery enigmas; glide over a sunken Italian city; a unique underwater cemetery in the Florida Keys; a yellow brick road to nowhere in the depths of the North Pacific; puzzling rocky constructions off the coast of Australia.

The science behind some of the most incredible engineering accidents ever filmed is revealed; a look at the physics involved as well as forensic details to explain the slip-ups that turned construction into destruction.

Using cutting-edge CGI, archive footage and expert interviews, examine mysterious curiosities that have been uncovered by extreme weather and calamitous incidents.

Vacationers end up trapped in a pool surrounded by fire; a Czech man faces a rare F4 tornado; an animal rescuer works in the aftermath of Hurricane Florence; a kayaker paddles through a pacific storm.

The science behind some of the most incredible engineering accidents ever filmed is revealed; a look at the physics involved as well as forensic details to explain the slip-ups that turned construction into destruction.

Contractor Mike Holmes joins forces with his children, Michael and Sherry, to continue his legacy of making it right and helping homeowners in need.

The Holmes team surprises superfan Michael, who has autism, with news that he's part of the crew; his family gets a life-changing upgrade that will open up their tired bungalow and give them more room for living.

Dealing with toxic fallout after a hot real estate market forces Jason and Alisha to buy a house without getting a home inspection; the Holmes team transforms a moldy, radon-filled eyesore into a cozy, healthy place to raise a family.

A buried ship, wartime cellars, jar burials and mass graves are excavated.

Encounter kids' drawings on the walls in Pompeii that expose the city's violent gladiatorial past; check out a mythical sculpture unearthed by an Indian tsunami, a 12-century temple in quake-prone Mexico; a sunken ship in Utah's Great Salt Lake.

A grim discovery in a Swedish lake reveals ancient practices; in the Canadian Arctic, the fossil of a previously unknown mammal is found; bizarre ice formations in the Antarctic Ocean; a discovery off the east coast of Canada.

Budding entrepreneurs get three minutes to pitch their business ideas to five multimillionaires who are willing to invest their own cash to kick-start the businesses in the original "Shark Tank." After each pitch, the Dragons have the opportunity to ask questions about the venture. The entrepreneurs don't always have to answer, but of course what they choose not to address could very well affect the outcome. The pitch is over when each of the Dragons has declared,"I'm out." Evan Davis hosts.

Explorers discover tunnel systems, a sprawling city, and military barracks.

Psychedelic swirls in the Utah wastelands; a bizarre configuration of circles in the Sahara; hidden lines with the help of a drone; a remote polka-dot lake in Canada.

A salvage team discovers the mysterious remains of an enormous shipwreck near Cambridge Bay in the icy waters of the Canadian Arctic; experts investigate and uncover a cutting-edge vessel with links to one of the greatest polar explorers in history.

Learning why an important urban center is sinking toward oblivion; soaring over sprawling ruins buried under Saharan sands; learning the modern secret of an ancient fortress; eyeing a ghost town on the edge of the Gobi.

Contestants compete across the series, scoring points by answering questions correctly; they must avoid the impossible answers, otherwise they will be eliminated until the next day.

Improv veterans Ryan Stiles, Wayne Brady and Colin Mochrie return for a new take on the comedy series with host, Aisha Tyler. Each episode, a special guest star joins the comics as they tackle a series of spontaneous improvised sketches, with only a few random ideas from the studio audience and their host. With little information and a lot of imagination, the comics depict a variety of characters and scenes, and even perform songs. At the end of each round, Aisha awards points to each of the four performers and announces a winner at the end of every episode.

Guest comic Jeff Davis.

Explores Schindler's Ark in the Czech Republic, a secret refuge in Europe's killing fields and a lost Amazonian paradise deep in the Brazilian rainforest.

Sweep away the debris in a Bronze Age village preserved by fire; open ancient sarcophagi found amid the rubble of Notre Dame; discover a grave hidden in a Canadian farmer's arid field; get intel on ancient climate change in a California tar pit.

Hurricane Sandy whips up wild waves in the Atlantic, prompting a rescue mission by the U.S. Coast Guard; cavers in California get caught out by flash floods; wild winds cause a crash for hot air balloonists; residents narrowly escape a landslide.

A salvage team discovers the mysterious remains of an enormous shipwreck near Cambridge Bay in the icy waters of the Canadian Arctic; experts investigate and uncover a cutting-edge vessel with links to one of the greatest polar explorers in history.

Sweep away the debris in a Bronze Age village preserved by fire; open ancient sarcophagi found amid the rubble of Notre Dame; discover a grave hidden in a Canadian farmer's arid field; get intel on ancient climate change in a California tar pit.

Hurricane Sandy whips up wild waves in the Atlantic, prompting a rescue mission by the U.S. Coast Guard; cavers in California get caught out by flash floods; wild winds cause a crash for hot air balloonists; residents narrowly escape a landslide.

Psychedelic swirls in the Utah wastelands; a bizarre configuration of circles in the Sahara; hidden lines with the help of a drone; a remote polka-dot lake in Canada.

A routine dental quickly becomes high-risk for a little Pomeranian, Bear; in Vanderhoof, a family brings in an abandoned dog who's in bad shape, searching for help from Dr. Cori; without owners present, questions arise about how to care for the dog.

Sandi Toksvig takes a look at some visionaries with Cally Beaton, Nish Kumar, Laura Smyth and Alan Davies.

Rhod Gilbert, Ignacio Lopez and Zoe Lyons join Sandi and Alan as QI goes viral.

Gyles Brandreth, Lulu and Emmanuel Sonubi join Sandi and Alan.

Alaskans push their limits amid the warming tundra and melting landscape.

A routine dental quickly becomes high-risk for a little Pomeranian, Bear; in Vanderhoof, a family brings in an abandoned dog who's in bad shape, searching for help from Dr. Cori; without owners present, questions arise about how to care for the dog.

Neil Delamere, Cariad Lloyd and Chris McCausland join Sandi and Alan.

Rhod Gilbert, Ignacio Lopez and Zoe Lyons join Sandi and Alan as QI goes viral.

Gyles Brandreth, Lulu and Emmanuel Sonubi join Sandi and Alan.

Improv veterans Ryan Stiles, Wayne Brady and Colin Mochrie return for a new take on the comedy series with host, Aisha Tyler. Each episode, a special guest star joins the comics as they tackle a series of spontaneous improvised sketches, with only a few random ideas from the studio audience and their host. With little information and a lot of imagination, the comics depict a variety of characters and scenes, and even perform songs. At the end of each round, Aisha awards points to each of the four performers and announces a winner at the end of every episode.

Guest comic Jeff Davis.

Hurricane Sandy whips up wild waves in the Atlantic, prompting a rescue mission by the U.S. Coast Guard; cavers in California get caught out by flash floods; wild winds cause a crash for hot air balloonists; residents narrowly escape a landslide.

Explores Schindler's Ark in the Czech Republic, a secret refuge in Europe's killing fields and a lost Amazonian paradise deep in the Brazilian rainforest.

A salvage team discovers the mysterious remains of an enormous shipwreck near Cambridge Bay in the icy waters of the Canadian Arctic; experts investigate and uncover a cutting-edge vessel with links to one of the greatest polar explorers in history.

Learning why an important urban center is sinking toward oblivion; soaring over sprawling ruins buried under Saharan sands; learning the modern secret of an ancient fortress; eyeing a ghost town on the edge of the Gobi.

Budding entrepreneurs get three minutes to pitch their business ideas to five multimillionaires who are willing to invest their own cash to kick-start the businesses in the original "Shark Tank." After each pitch, the Dragons have the opportunity to ask questions about the venture. The entrepreneurs don't always have to answer, but of course what they choose not to address could very well affect the outcome. The pitch is over when each of the Dragons has declared,"I'm out." Evan Davis hosts.

The science behind some of the most incredible engineering accidents ever filmed is revealed; a look at the physics involved as well as forensic details to explain the slip-ups that turned construction into destruction.

Get petrified by cryptic rock structures normally hidden from view; look inside curious dwellings in the Peruvian Andes; visit a sacred monolith in Wyoming's Black Hills; haunt a Turkish stone village; spot an immovable waterfall in Mexico.

Mountain climbers in California find the body of a U.S. Army soldier; strange bundles of canvas and wood are discovered on an Alaskan mountain; volcanic glass is found in an unexpected place; a vital World War II weather station is uncovered.

Investigating notable UFO and extraterrestrial cases from the past 75 years, applying analytical techniques to examine the historical context and evidence behind these unexplained phenomena.

Fire up another heat of competition as the players try to tease out which of Rick's answers are not just wrong but actually impossible; hang tight through three tense rounds and see who is left standing to face the 10,000-pound exclamation point.

Guest comic Jordin Sparks.

Guest comic Chris Lee.

Inspect a decaying New Jersey facility that was a powder keg of injustice; tour a Polish imperial bastion-turned-movie-set; visit an English country retreat that harbored radical fugitives and a Namibian outpost funded by desert treasures.

Analyze fish remains found near an angry Sumatran volcano that could suggest a new human migration route; visit a prehistoric village smoked out by a forest fire, a collapsed kingdom in Turkey, and evidence of early Olympic sacrificial rituals.

A twister outbreak in Texas leaves a storm chaser trapped; in Florida, dangerous riptides drag swimmers out to sea; a sudden storm hits a holiday resort in Greece; a giant wave crashes through a restaurant in Italy.

Mountain climbers in California find the body of a U.S. Army soldier; strange bundles of canvas and wood are discovered on an Alaskan mountain; volcanic glass is found in an unexpected place; a vital World War II weather station is uncovered.

Analyze fish remains found near an angry Sumatran volcano that could suggest a new human migration route; visit a prehistoric village smoked out by a forest fire, a collapsed kingdom in Turkey, and evidence of early Olympic sacrificial rituals.

A twister outbreak in Texas leaves a storm chaser trapped; in Florida, dangerous riptides drag swimmers out to sea; a sudden storm hits a holiday resort in Greece; a giant wave crashes through a restaurant in Italy.

Get petrified by cryptic rock structures normally hidden from view; look inside curious dwellings in the Peruvian Andes; visit a sacred monolith in Wyoming's Black Hills; haunt a Turkish stone village; spot an immovable waterfall in Mexico.

Catastrophe strikes a crucial allied air supply route in WWII as 15 planes never return; London's River Thames ices up so much, a fair is held on it; a mission to the Moon narrowly avoids disaster.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

Inspect a decaying New Jersey facility that was a powder keg of injustice; tour a Polish imperial bastion-turned-movie-set; visit an English country retreat that harbored radical fugitives and a Namibian outpost funded by desert treasures.

Catastrophe strikes a crucial allied air supply route in WWII as 15 planes never return; London's River Thames ices up so much, a fair is held on it; a mission to the Moon narrowly avoids disaster.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

Guest comic Jordin Sparks.

Guest comic Chris Lee.

A twister outbreak in Texas leaves a storm chaser trapped; in Florida, dangerous riptides drag swimmers out to sea; a sudden storm hits a holiday resort in Greece; a giant wave crashes through a restaurant in Italy.

Inspect a decaying New Jersey facility that was a powder keg of injustice; tour a Polish imperial bastion-turned-movie-set; visit an English country retreat that harbored radical fugitives and a Namibian outpost funded by desert treasures.

Mountain climbers in California find the body of a U.S. Army soldier; strange bundles of canvas and wood are discovered on an Alaskan mountain; volcanic glass is found in an unexpected place; a vital World War II weather station is uncovered.

Investigating notable UFO and extraterrestrial cases from the past 75 years, applying analytical techniques to examine the historical context and evidence behind these unexplained phenomena.

Budding entrepreneurs get three minutes to pitch their business ideas to five multimillionaires who are willing to invest their own cash to kick-start the businesses in the original "Shark Tank." After each pitch, the Dragons have the opportunity to ask questions about the venture. The entrepreneurs don't always have to answer, but of course what they choose not to address could very well affect the outcome. The pitch is over when each of the Dragons has declared,"I'm out." Evan Davis hosts.

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

Witness animal spectacles from high above the Earth; watch a whirling herd of northern nomads; see undersea behemoths show off in the Pacific shallows; track a U.S. porcine stampede; confront top ocean predators on the Florida coast.

Archaeologists make a grim discovery when they uncover the remains of a mummified boy buried in the frozen Siberian landscape, and as researchers continue their excavation, they uncover 88 additional graves linked to a mysterious, ancient necropolis.

The first sightings of the UFO flap in Piedmont, Mo. are reported; Over 500 reports are made in the following months; A family driving to Ontario encounters mysterious lights and a cigar-shaped craft.

Cousins Billy and John Smith encounter a massive ship triple the size of a football stadium; guards at Malmstrom Air Force Base in Montana spot an unidentified object overhead.

Contestants compete across the series, scoring points by answering questions correctly; they must avoid the impossible answers, otherwise they will be eliminated until the next day.

Guest comic Greg Proops.

Games include: Questions, Doo Wop, Dubbing, Scenes from a hat, Helping hands.

A Polish castle becomes entwined in the hunt for lost Nazi treasure, the heir of an American business tycoon gets caught in a web of controversy, and an Irish estate is embroiled in a fight for freedom.

Dig into artifacts from a multicultural Jamaican port sunk by a devastating earthquake; get insights into every day Mesoamerican life next to a Salvadoran volcano; peek at a Minoan landmark; inspect a treasure trove of English relics.

Join the LA fire department as it rescues wildfire-trapped residents, then face the fury of the biggest tornado to hit the US in 60 years. Brave extreme elements with daredevil skydivers in Antarctica and see a Texas microburst cause carnage.

Archaeologists make a grim discovery when they uncover the remains of a mummified boy buried in the frozen Siberian landscape, and as researchers continue their excavation, they uncover 88 additional graves linked to a mysterious, ancient necropolis.

Dig into artifacts from a multicultural Jamaican port sunk by a devastating earthquake; get insights into every day Mesoamerican life next to a Salvadoran volcano; peek at a Minoan landmark; inspect a treasure trove of English relics.

Join the LA fire department as it rescues wildfire-trapped residents, then face the fury of the biggest tornado to hit the US in 60 years. Brave extreme elements with daredevil skydivers in Antarctica and see a Texas microburst cause carnage.

Witness animal spectacles from high above the Earth; watch a whirling herd of northern nomads; see undersea behemoths show off in the Pacific shallows; track a U.S. porcine stampede; confront top ocean predators on the Florida coast.

In a Danish bog, hundreds of mutilated ancient bones are found, while a mysterious deserted island belonging to Russia is explored.

On the island of Pohnpei in Micronesia, explorers discover ancient structures hidden beneath dense vegetation; a strange glowing forest is discovered in India; an immense tunnel system is investigated in the Brazilian jungle.

Scan the skeleton of a drowned Stone Age fisherman in Chile and rediscover a vanished golden age in Egypt's lost city of Aten; ancient Chinese mummies reignite a cultural debate; discover a massive biblical-era moat in Jerusalem.

In a Danish bog, hundreds of mutilated ancient bones are found, while a mysterious deserted island belonging to Russia is explored.

On the island of Pohnpei in Micronesia, explorers discover ancient structures hidden beneath dense vegetation; a strange glowing forest is discovered in India; an immense tunnel system is investigated in the Brazilian jungle.

Guest comic Greg Proops.

Games include: Questions, Doo Wop, Dubbing, Scenes from a hat, Helping hands.

Join the LA fire department as it rescues wildfire-trapped residents, then face the fury of the biggest tornado to hit the US in 60 years. Brave extreme elements with daredevil skydivers in Antarctica and see a Texas microburst cause carnage.

A Polish castle becomes entwined in the hunt for lost Nazi treasure, the heir of an American business tycoon gets caught in a web of controversy, and an Irish estate is embroiled in a fight for freedom.

The magnificent tomb of Alexander the Great mysteriously vanishes and becomes a legend; using CGI, investigators piece together the evidence to reveal where his tomb lies and what it might look like.

The first sightings of the UFO flap in Piedmont, Mo. are reported; Over 500 reports are made in the following months; A family driving to Ontario encounters mysterious lights and a cigar-shaped craft.

Cousins Billy and John Smith encounter a massive ship triple the size of a football stadium; guards at Malmstrom Air Force Base in Montana spot an unidentified object overhead.

Budding entrepreneurs get three minutes to pitch their business ideas to five multimillionaires who are willing to invest their own cash to kick-start the businesses in the original "Shark Tank." After each pitch, the Dragons have the opportunity to ask questions about the venture. The entrepreneurs don't always have to answer, but of course what they choose not to address could very well affect the outcome. The pitch is over when each of the Dragons has declared,"I'm out." Evan Davis hosts.

Investigating notable UFO and extraterrestrial cases from the past 75 years, applying analytical techniques to examine the historical context and evidence behind these unexplained phenomena.

Investigating significant historic and contemporary sites from the revealing vantage points of drone, satellite and aerial photography.

An unidentified metal object is found on Kiska Island; a centuries-old gold mining mystery is investigated; in Siberia, a network of ice tunnels is explored; fossils unearthed in the Canadian Arctic lead to the discovery of a new species.

Chief Brett Lovegrove, former Head of Counterterrorism for City of London Police, runs a team of 30 hunters, carefully selected from law enforcement, military intelligence and human tracking; their first fugitive is Dr. Ricky Allen from Kent.

Say goodbye to this group of players, who are ready for a last shot at the cash.

Improv veterans Ryan Stiles, Wayne Brady and Colin Mochrie return for a new take on the comedy series with host, Aisha Tyler. Each episode, a special guest star joins the comics as they tackle a series of spontaneous improvised sketches, with only a few random ideas from the studio audience and their host. With little information and a lot of imagination, the comics depict a variety of characters and scenes, and even perform songs. At the end of each round, Aisha awards points to each of the four performers and announces a winner at the end of every episode.

Guest comic Jeff Davis.

Meeting the people who designed amazing engineering projects and those that help revive them.

A sprawling military facility dotted with bunkers for miles now stands abandoned in the American heartland of Edgemont, S.D.; experts investigate and uncover a once highly-secure WWII ordnance site designed to store deadly munitions.

Queensland, Australia is shaken by the most devastating flood in its history; in Kansas, two storm chasers track a terrifying twister; a base jumper gets stranded in freezing temperatures in Iceland; a destructive hail storm pummels Texas.

An unidentified metal object is found on Kiska Island; a centuries-old gold mining mystery is investigated; in Siberia, a network of ice tunnels is explored; fossils unearthed in the Canadian Arctic lead to the discovery of a new species.

A sprawling military facility dotted with bunkers for miles now stands abandoned in the American heartland of Edgemont, S.D.; experts investigate and uncover a once highly-secure WWII ordnance site designed to store deadly munitions.

Queensland, Australia is shaken by the most devastating flood in its history; in Kansas, two storm chasers track a terrifying twister; a base jumper gets stranded in freezing temperatures in Iceland; a destructive hail storm pummels Texas.

Investigating significant historic and contemporary sites from the revealing vantage points of drone, satellite and aerial photography.

Hugh Jackman, Kate Hudson, Ben Stiller, Da'Vine Joy Randolph and singer-songwriter Sombr perform his single 12 to 12.

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

Guest comic Jordin Sparks.

Guest comic Chris Lee.

Hugh Jackman, Kate Hudson, Ben Stiller, Da'Vine Joy Randolph and singer-songwriter Sombr perform his single 12 to 12.

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

Say goodbye to this group of players, who are ready for a last shot at the cash.

Queensland, Australia is shaken by the most devastating flood in its history; in Kansas, two storm chasers track a terrifying twister; a base jumper gets stranded in freezing temperatures in Iceland; a destructive hail storm pummels Texas.

Meeting the people who designed amazing engineering projects and those that help revive them.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

On the flanks of a volcano, lava appears that astonishingly burns bright blue; a creepy orange entity pulses threateningly at the bottom of a partially frozen pond; a huge, sinister dark blob invades a popular beach.

Leaders and representatives of Aboriginal communities show Zac and Darin how indigenous cultures live to protect and preserve the land.

Using cutting-edge CGI, archive footage and expert interviews, examine mysterious curiosities that have been uncovered by extreme weather and calamitous incidents.

The science behind some of the most incredible engineering accidents ever filmed is revealed; a look at the physics involved as well as forensic details to explain the slip-ups that turned construction into destruction.

In a Danish bog, hundreds of mutilated ancient bones are found, while a mysterious deserted island belonging to Russia is explored.

Budding entrepreneurs get three minutes to pitch their business ideas to five multimillionaires who are willing to invest their own cash to kick-start the businesses in the original "Shark Tank." After each pitch, the Dragons have the opportunity to ask questions about the venture. The entrepreneurs don't always have to answer, but of course what they choose not to address could very well affect the outcome. The pitch is over when each of the Dragons has declared,"I'm out." Evan Davis hosts.

Guest comic Jordin Sparks.

Paid programming.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

The science behind some of the most incredible engineering accidents ever filmed is revealed; a look at the physics involved as well as forensic details to explain the slip-ups that turned construction into destruction.

Hugh Jackman, Kate Hudson, Ben Stiller, Da'Vine Joy Randolph and singer-songwriter Sombr perform his single 12 to 12.

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

Sandi Toksvig takes a look at some visionaries with Cally Beaton, Nish Kumar, Laura Smyth and Alan Davies.

Neil Delamere, Cariad Lloyd and Chris McCausland join Sandi and Alan.

Budding entrepreneurs get three minutes to pitch their business ideas to five multimillionaires who are willing to invest their own cash to kick-start the businesses in the original "Shark Tank." After each pitch, the Dragons have the opportunity to ask questions about the venture. The entrepreneurs don't always have to answer, but of course what they choose not to address could very well affect the outcome. The pitch is over when each of the Dragons has declared,"I'm out." Evan Davis hosts.

Rick welcomes 24 new contestants, who all want a chance to make 10,000 one-pound coins rain from the giant exclamation point on stage; seeing who wins by keeping their cool and dodging the impossible answers.

Sandi Toksvig takes a look at some visionaries with Cally Beaton, Nish Kumar, Laura Smyth and Alan Davies.

Neil Delamere, Cariad Lloyd and Chris McCausland join Sandi and Alan.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

For many years, Heather Mason (Adelaide Clemens) and her father, Harry (Sean Bean), have been on the run from dangerous forces she does not understand. Heather continues to be plagued by terrifying nightmares and frightened by her father's disappearance, and on the eve of her 18th birthday, she discovers that she is not who she thinks she is. The revelation leads her deep into the demonic world of Silent Hill, where she may become trapped forever.

Catastrophe strikes a crucial allied air supply route in WWII as 15 planes never return; London's River Thames ices up so much, a fair is held on it; a mission to the Moon narrowly avoids disaster.

In a Danish bog, hundreds of mutilated ancient bones are found, while a mysterious deserted island belonging to Russia is explored.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

Using cutting-edge CGI, archive footage and expert interviews, examine mysterious curiosities that have been uncovered by extreme weather and calamitous incidents.

Catastrophe strikes a crucial allied air supply route in WWII as 15 planes never return; London's River Thames ices up so much, a fair is held on it; a mission to the Moon narrowly avoids disaster.

The science behind some of the most incredible engineering accidents ever filmed is revealed; a look at the physics involved as well as forensic details to explain the slip-ups that turned construction into destruction.

Budding entrepreneurs get three minutes to pitch their business ideas to five multimillionaires who are willing to invest their own cash to kick-start the businesses in the original "Shark Tank." After each pitch, the Dragons have the opportunity to ask questions about the venture. The entrepreneurs don't always have to answer, but of course what they choose not to address could very well affect the outcome. The pitch is over when each of the Dragons has declared,"I'm out." Evan Davis hosts.

Psychedelic swirls in the Utah wastelands; a bizarre configuration of circles in the Sahara; hidden lines with the help of a drone; a remote polka-dot lake in Canada.

Dr. Cori sees it all, from stray puppies and anxious dogs with persistent paw injuries, to horses needing dental work. Dr. Allison tackles a growing lump on cuddly Jorah and takes an x-ray that means bad news for an older dog.

Dr. Allison and her team must monitor Shelby the Shih Tzu while trying to remove hundreds of tiny, grainy bladder stones; in Calgary, Dr. Emma and her team try to wrangle dogs for a blood drive.

Using cutting-edge CGI, archive footage and expert interviews, examine mysterious curiosities that have been uncovered by extreme weather and calamitous incidents.

Volunteers unearth tunnel systems, and a sealed burial tomb is found.

The science behind some of the most incredible engineering accidents ever filmed is revealed; a look at the physics involved as well as forensic details to explain the slip-ups that turned construction into destruction.

Guest comic Greg Proops.

Paid programming.

In 1978, UFO enthusiast Paul Bennewitz claims he's intercepted extraterrestrial messages; military officials send counterintelligence officer Richard Doty to feed Bennewitz lies, questioning whether Doty himself is a pawn in an even bigger scheme.

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

Will Kirk and Christina Trevanion take their mobile auction house on the road.

Rhod Gilbert, Ignacio Lopez and Zoe Lyons join Sandi and Alan as QI goes viral.

Gyles Brandreth, Lulu and Emmanuel Sonubi join Sandi and Alan.

Will Kirk and Christina Trevanion take their mobile auction house on the road.

Caroline Aherne narrates as some of Britain's most opinionated viewers comment freely.

Alaskans push their limits amid the warming tundra and melting landscape.

Get petrified by cryptic rock structures normally hidden from view; look inside curious dwellings in the Peruvian Andes; visit a sacred monolith in Wyoming's Black Hills; haunt a Turkish stone village; spot an immovable waterfall in Mexico.