Discover the locations of stargate portals around the world. Thought to be doorways to wormholes in time, who is battling to open them and why.

Discover the secrets surrounding the ten biggest and most mysterious conspiracies in history, including the goings-on at Area 51.

In this episode, each competitor is tasked with creating their very own original cartoon character made of glass.

In this episode, each competitor is tasked with creating a special piece inspired by the phenomenon of climate change.

Ancient Astronaut theorists suggest that aliens have been guiding mankind in secret to bring about huge leaps in technological advancement.

Examining claims that extraordinary discoveries are being ignored by the scientific community for not conforming to their accepted paradigm.

The Seeds of Violence 1918-1922: In the wake of the First World War, Adolf Hitler identifies Benito Mussolini as his model and has one ultimate goal: to gain power in Germany.

Racing an incoming hurricane, Darrell and his team are forced to make tough choices - but they finally locate the source of a massive magnetometer hit.

During WWII, the French Resistance seeks aid from SOE. Led by Vera Atkins, Odette Sansom and Noor Inayat Khan fight the Nazis, risking it all for victory.

Ancient Astronaut theorists suggest that aliens have been guiding mankind in secret to bring about huge leaps in technological advancement.

Examining claims that extraordinary discoveries are being ignored by the scientific community for not conforming to their accepted paradigm.

Another visit to the north for Alice, checking out evidence of early writing by the Picts in Scotland and a 3,000-year-old Bronze Age coffin.

Excavations in southern England uncover a lost Roman town, a Tudor ship and evidence of Henry VIII's financial forgery at the Tower of London.

In the west of the UK, explore a spectacular monument older than Stonehenge, a 200-year-old mine trapped in time and a lost medieval friary.

Explore a gatehouse full of Civil War bullets, an Iron Age shield made from bark and Roman burials with pots where the heads should be.

Alice Roberts reveals a Dutch ship sunk by the English, a Cornish Roman fort and a 5,000-year-old Neolithic monument.

The team investigate a legendary man-eating croc, glowing lights in Mexico and chilling footage of a pair of dogs.

Racing an incoming hurricane, Darrell and his team are forced to make tough choices - but they finally locate the source of a massive magnetometer hit.

In a world without humans, water turns from life-giver to destroyer, flooding cities, collapsing dams and triggering ancient forces long kept at bay.

Is a picture taken in the 1890s the first Bigfoot photo ever.

Tony Harris breaks down the most shocking moments ever caught on camera.

Ancient Astronaut theorists suggest that aliens have been guiding mankind in secret to bring about huge leaps in technological advancement.

Examining claims that extraordinary discoveries are being ignored by the scientific community for not conforming to their accepted paradigm.

A team of experts investigate some of the most well-known UFO cases of the last 75 years, hoping to uncover the truth.

Hugh and the experts attempt to uncover a lost Roman fort connected to the Antonine Wall, buried beneath the gardens of the quiet streets of Falkirk.

Another visit to the north for Alice, checking out evidence of early writing by the Picts in Scotland and a 3,000-year-old Bronze Age coffin.

See a giant glacier on Mars, milky seas near Java, a hexagon over Saturn and a doughnut-shaped lake in Saskatchewan.

Sheldon Smithens and Scott Cozens travel across the country looking for hidden treasures and antiques in people's basements, sheds, attics and barns.

As science turns towards augmenting humanity with technology, theorists suggest that we are merely following the path of our alien creators.

The ancient metropolis of Teotihuacan, called The City of The Gods by the Aztecs, is a site of great mystery. Could alien beings have once lived there.

Deceit and Delusion 1923-1928: Hitler appears to be eliminated after his failed putsch in 1923. Discover how the Nazi movement used democracy's tolerance in Germany to come back.

World War II breaks out and a force of U-boats attempt to starve Britain into submission. Meanwhile, Vera Laughton Mathews recruits talented women into the Wrens.

Vera enlists Violette Szabo and Yvonne Baseden. With circuits failing and Noor at risk, treachery allegations harm preparations for the Allied invasion.

As science turns towards augmenting humanity with technology, theorists suggest that we are merely following the path of our alien creators.

The ancient metropolis of Teotihuacan, called The City of The Gods by the Aztecs, is a site of great mystery. Could alien beings have once lived there.

Near the Czech border, a secret German site, "The Giant," tests The Bell, powered by Serum 525, turning all who touch it into rotting living zombies.

A 23-year-old Hitler, living hand-to-mouth as a painter in Vienna, Austria, discovers a sacred spear in the city's Hofburg Museum.

In 1943, the inmates of the Death Camp at Sobibor staged an organised rebellion against their Nazi oppressors.

Near the Czech border, a secret German site, "The Giant," tests The Bell, powered by Serum 525, turning all who touch it into rotting living zombies.

1942 and Hitler has the totally barking idea of using educated dogs to do a soldier's job. The Nazi leader wants to create fearsome canines to help him win the Second World War.

The team examine a strange UFO sighting, the sudden appearance of a red sea and possible proof of a Yeti.

World War II breaks out and a force of U-boats attempt to starve Britain into submission. Meanwhile, Vera Laughton Mathews recruits talented women into the Wrens.

During WWII, the French Resistance seeks aid from SOE. Led by Vera Atkins, Odette Sansom and Noor Inayat Khan fight the Nazis, risking it all for victory.

Vera enlists Violette Szabo and Yvonne Baseden. With circuits failing and Noor at risk, treachery allegations harm preparations for the Allied invasion.

The 1717 wreck of Black Sam Bellamy's pirate ship Whydah yields treasure, skeletons and new insights into the hidden world of piracy.

As science turns towards augmenting humanity with technology, theorists suggest that we are merely following the path of our alien creators.

The ancient metropolis of Teotihuacan, called The City of The Gods by the Aztecs, is a site of great mystery. Could alien beings have once lived there.

Beyond Nazca: Giorgio Tsoukalos draws on evidence from past series as he takes an in-depth look at the mystery of Southern Peru's Nasca Lines.

In Stretton, Hugh and the team search for prehistoric roundhouses and try to work out when people first made the Staffordshire village their home.

Excavations in southern England uncover a lost Roman town, a Tudor ship and evidence of Henry VIII's financial forgery at the Tower of London.

Explore strongholds abandoned by their architects, look at a lost city in the Amazon jungle and see a desert fortress made by humanity's most notorious empire.

The guys are in Quebec's Eastern Townships, where they visit a home filled with 200-year-old antiques.

Ancient Astronaut theorists look at the Aborigine legend of Dreamtime, and ask if these stories hold the proof that aliens created life on Earth.

Different cultures have used mantras and chanting for thousands of years - could these in fact be a method of communing with extraterrestrial forces.

Democracy Without Democrats 1929-1933: A protest turns into a racist and anti-Jewish movement during the 1920s and the NSDAP use emotions to gain the loyalty of the people.

France falls in 1940 and Donitz's U-boats embark on a race to sink British merchant ships. Roberts' wargaming ideas are at last entertained by a desperate Admiralty.

With Allied victories and the liberation of Paris following D-Day, Vera is in a race against time to locate her missing agents.

Ancient Astronaut theorists look at the Aborigine legend of Dreamtime, and ask if these stories hold the proof that aliens created life on Earth.

Different cultures have used mantras and chanting for thousands of years - could these in fact be a method of communing with extraterrestrial forces.

Experts investigate startling evidence suggesting that the Ancient Maya conspired with aliens. Was this how they acquired their knowledge of astrology.

Experts scrutinise the Maya Calendar, which predicted the world would end in 2012. Could it have anticipated the arrival of an extraterrestrial god.

Experts investigate the 'greys' - mysterious beings with big heads and eyes found carved into rocks. Who are these strange figures and what inspired them.

Did Mother Nature cause the volcanoes, earthquakes and floods of ancient times? Or could aliens have been responsible? Experts investigate.

Experts open up NASA and secret government files. Can they find proof of alien contact in the recent or ancient past.

The team explore possible proof of a sea monster, a tale of a skydive gone wrong, and a ghostly image.

France falls in 1940 and Donitz's U-boats embark on a race to sink British merchant ships. Roberts' wargaming ideas are at last entertained by a desperate Admiralty.

With Allied victories and the liberation of Paris following D-Day, Vera is in a race against time to locate her missing agents.

Armed with evidence from Odette, Vera intensifies her search at Karlsruhe prison and Ravensbruck, facing hurdles to uncover crucial results in Germany.

Journey back in time to understand the brainpower behind Ancient Egypt's revolutionary breakthroughs in every field, from medicine to engineering.

Ancient Astronaut theorists look at the Aborigine legend of Dreamtime, and ask if these stories hold the proof that aliens created life on Earth.

Different cultures have used mantras and chanting for thousands of years - could these in fact be a method of communing with extraterrestrial forces.

The Monoliths: Giorgio Tsoukalos takes a closer look at the evidence as he asks whether Earth's stone monoliths were built with extra terrestrial help.

Hugh Dennis and a team of archaeologists are in Devizes, searching for a revolutionary 19th-century prison with a unique design.

In the west of the UK, explore a spectacular monument older than Stonehenge, a 200-year-old mine trapped in time and a lost medieval friary.

Fly over an imperial pyramid in the Netherlands, a metal sphere in Russia, a lion in England and a swath in an Austrian forest.

Sheldon Smithens and Scott Cozens travel across the country looking for hidden treasures and antiques in people's basements, sheds, attics and barns.

Could claims of "The Nine" - a federation of extraterrestrial beings who monitor and influence mankind - have any credence? Experts believe so.

Did a top secret group of officials, dubbed the Majestic Twelve, really create a space programme that has already established bases on the moon.

The Racial State 1933-1934: President Hindenburg suspends freedom of speech and Hitler comes to power in 1933. The first concentration camps for political opponents are set up.

Though the Admiralty are convinced the Allies have the expertise to defeat Germany, Roberts and the Wrens start devising wargaming tactics to combat U-boat formations.

Armed with evidence from Odette, Vera intensifies her search at Karlsruhe prison and Ravensbruck, facing hurdles to uncover crucial results in Germany.

Could claims of "The Nine" - a federation of extraterrestrial beings who monitor and influence mankind - have any credence? Experts believe so.

Did a top secret group of officials, dubbed the Majestic Twelve, really create a space programme that has already established bases on the moon.

A bright pink lake could point to a strange, undiscovered new species. When a young boy disappears in a sand dune, satellite images help with the investigation.

Investigators find a new clue about the missing Malaysia Airlines flight that disappeared in 2014, and an astronaut spots something strange in the Sahara Desert.

An ominous shadow engulfs the Pacific Ocean and scientists have trouble explaining a strange lake that's shaped like a perfect circle.

A dagger sealed in King Tut's tomb for over 3,000 years is made of a possibly extraterrestrial metal. A huge swastika is found in the desert near Roswell.

A heavily armoured force takes over one of Syria's most ancient archaeological sites, prompting fears that its relics are being stolen.

The team investigate footage of a witch's broomstick, extraterrestrial goings-on and blobs falling from the sky.

Though the Admiralty are convinced the Allies have the expertise to defeat Germany, Roberts and the Wrens start devising wargaming tactics to combat U-boat formations.

Vera finds out her agents' fate. Her beliefs about Noor are challenged. Suspicions lead Vera to hunt down a Nazi mastermind.

This episode delves into Hitler's controlling sexual nature. The four women pursued by him, including his niece, only saw one way out of the relationship - death.

In his role as Adolf Hitler's favourite architect, Albert Speer was a central figure in the Fuhrer's inner circle and helped cement his position in power.

Could claims of "The Nine" - a federation of extraterrestrial beings who monitor and influence mankind - have any credence? Experts believe so.

Did a top secret group of officials, dubbed the Majestic Twelve, really create a space programme that has already established bases on the moon.

The Tesla Experiment. Giorgio A Tsoukalos draws on evidence from past series as he asks whether Nikola Tesla was communicating with extraterrestrials.

Can Hugh and the team find the remains of a vanished building in the gardens of the Georgian stately home Beningbrough Hall.

Explore a gatehouse full of Civil War bullets, an Iron Age shield made from bark and Roman burials with pots where the heads should be.

Discover familiar stone monoliths in Colombia, explore a lost city in Sierra Nevada and unravel ancient ruins in Greece and Malta.

After months on the road and with their warehouse overflowing, the guys invite their antique dealer friends over for a sales extravaganza.

Ancient Astronaut theorists suggest that China, with its history of technological advancement and isolationism, could have been the home of alien beings.

Experts question if Cloud computing represents the rediscovery of an ancient repository of knowledge known as the Akashic Record.

Hidden In Plain Sight 1935-1938: In 1934, Hitler's government is firmly in the saddle. Most Germans support Hitler's anti-Jewish policy and the regime's terror soon escalates.

Roberts and Laidlaw uncover a fatal flaw in the Royal Navy's anti-U-boat strategy and develop their own countertactic. Their next task is winning over the Admiralty.

Vera finds out her agents' fate. Her beliefs about Noor are challenged. Suspicions lead Vera to hunt down a Nazi mastermind.

Ancient Astronaut theorists suggest that China, with its history of technological advancement and isolationism, could have been the home of alien beings.

Experts question if Cloud computing represents the rediscovery of an ancient repository of knowledge known as the Akashic Record.

The USS Enterprise became the first ship to receive the Presidential Unit Citation in WWII, following its mission during the bloody Gilbert invasion.

Follow the events of 1944, as the USS Enterprise and the Carrier Task Force push through the Pacific, hammering the enemy bases at Kwajalein and Truk Lagoon.

While the Allies storm France, American forces hit the Marianas Islands and the Enterprise supports one of the most deadly battles of the Pacific War.

Follow the events as the USS Enterprise engages in one of the largest sea battles of the war.

As the US Navy closes in on Okinawa and the Japanese homeland, the Empire unleashes a hellish weapon. Will the Enterprise survive the Kamikaze.

Veterans Rudy and Ronnie reveal the truth behind a nuclear sub sinking, WW2 bomber explosion, Goldsboro near-catastrophe, and a Vietnam disaster.

Roberts and Laidlaw uncover a fatal flaw in the Royal Navy's anti-U-boat strategy and develop their own countertactic. Their next task is winning over the Admiralty.

Capture of a key Nazi uncovers shocking realities. Amid demands for accountability, as Vera and her team navigate murky waters to confront uncomfortable truths.

From secret nuclear programs to hidden Cold War bunkers, we uncover the surprising people and places behind top-secret discoveries.

The legendary treasures of the Copper Scroll, King Solomon's mines and the Syamantaka Gem.

Ancient Astronaut theorists suggest that China, with its history of technological advancement and isolationism, could have been the home of alien beings.

Experts question if Cloud computing represents the rediscovery of an ancient repository of knowledge known as the Akashic Record.

Alien Power Plants: Giorgio Tsoukalos draws on evidence from past series as he asks whether aliens introduced the Greeks and Egyptians to electricity.

Hugh and the team search for the remains of a Norman motte and bailey castle in the suburb of West Derby and uncover gems in the residents' gardens.

Alice Roberts reveals a Dutch ship sunk by the English, a Cornish Roman fort and a 5,000-year-old Neolithic monument.

Face bizarre sights: a spinning island in Argentina, a desert triangle, Ethiopia's colourful pools and a giant figure in Australia's outback.

The guys are in Ontario and think they've hit the jackpot - first stop is a sprawling property with so many outbuildings it could double as a village.

Experts investigate startling evidence suggesting that the Ancient Maya conspired with aliens. Was this how they acquired their knowledge of astrology.

Experts scrutinise the Maya Calendar, which predicted the world would end in 2012. Could it have anticipated the arrival of an extraterrestrial god.

During WWII, the French Resistance seeks aid from SOE. Led by Vera Atkins, Odette Sansom and Noor Inayat Khan fight the Nazis, risking it all for victory.

With Allied victories and the liberation of Paris following D-Day, Vera is in a race against time to locate her missing agents.

World War II breaks out and a force of U-boats attempt to starve Britain into submission. Meanwhile, Vera Laughton Mathews recruits talented women into the Wrens.

Another visit to the north for Alice, checking out evidence of early writing by the Picts in Scotland and a 3,000-year-old Bronze Age coffin.

Excavations in southern England uncover a lost Roman town, a Tudor ship and evidence of Henry VIII's financial forgery at the Tower of London.

In the west of the UK, explore a spectacular monument older than Stonehenge, a 200-year-old mine trapped in time and a lost medieval friary.

Experts investigate startling evidence suggesting that the Ancient Maya conspired with aliens. Was this how they acquired their knowledge of astrology.

Experts scrutinise the Maya Calendar, which predicted the world would end in 2012. Could it have anticipated the arrival of an extraterrestrial god.

A chronological telling of the dramatic D-Day story, focusing on the vessels that made the landings possible.

From the trench to the home front hospital, a medical historian retraces the train journey made by wounded soldiers during World War I.

The story of one American GI and how he and his Harley motorbike became a legend.

Attila, king of the Huns, faces strongman of the Roman Empire, Generalissimo Aetius. But their terrible battle ends in a bloodbath, with no clear victory.

The Battle of Sekigahara saw Tokugawa Ieyasu emerge victorious over his rival Ishida Mitsunari, uniting the country under the Tokugawa shogunate.

Armageddon 1943-1945: The defeat at Stalingrad in 1943 was the turning point of the war and convinced the Nazi leadership to intensify their terror and propaganda campaigns.

The Reckoning 1945-1948: In 1945, WWII was over but the violence had not ended. The survivors want to blame the Germans. The reckoning with National Socialism is ambivalent.

Experts investigate startling evidence suggesting that the Ancient Maya conspired with aliens. Was this how they acquired their knowledge of astrology.

Experts scrutinise the Maya Calendar, which predicted the world would end in 2012. Could it have anticipated the arrival of an extraterrestrial god.

A new report is made every 55 hours in Washington state, which is America's highest rate of UFO sightings per capita - but why are UFOs choosing to hover here.

Discover the key role scientific pioneers played in reshaping our solar system. Plus, learn how technology helped humans explore its furthest reaches.

The story of one American GI and how he and his Harley motorbike became a legend.

Examine a tablet linked to a lost civilisation, a machine that measures beauty and an ancient Egyptian object.

Designed on the medieval model of forts with its enclosure and large corner towers, Chambord is France's largest and most iconic castle.

Experts investigate the 'greys' - mysterious beings with big heads and eyes found carved into rocks. Who are these strange figures and what inspired them.

Did Mother Nature cause the volcanoes, earthquakes and floods of ancient times? Or could aliens have been responsible? Experts investigate.

Vera enlists Violette Szabo and Yvonne Baseden. With circuits failing and Noor at risk, treachery allegations harm preparations for the Allied invasion.

Armed with evidence from Odette, Vera intensifies her search at Karlsruhe prison and Ravensbruck, facing hurdles to uncover crucial results in Germany.

France falls in 1940 and Donitz's U-boats embark on a race to sink British merchant ships. Roberts' wargaming ideas are at last entertained by a desperate Admiralty.

Explore a gatehouse full of Civil War bullets, an Iron Age shield made from bark and Roman burials with pots where the heads should be.

Alice Roberts reveals a Dutch ship sunk by the English, a Cornish Roman fort and a 5,000-year-old Neolithic monument.

Starting on the Isle of Lewis in the Outer Hebrides, witness the 5,000-year-old standing stones of Callanish, traditional Scottish blackhouses, and cut peat with a modern crofter.

Experts investigate the 'greys' - mysterious beings with big heads and eyes found carved into rocks. Who are these strange figures and what inspired them.

Did Mother Nature cause the volcanoes, earthquakes and floods of ancient times? Or could aliens have been responsible? Experts investigate.

In the Philippines, archaeologists discover the remains of an ancient rhinoceros. Elsewhere, a Brazilian island is infested with thousands of vipers.

In the northwestern Pacific, a tourist stumbles across a mysterious structure. Elsewhere, an unsettling sight is revealed on the island of New Guinea.

Amazing CGI graphics tell the story of how the USS Enterprise and sister carriers Yorktown and Hornet turned the tide of the Pacific battle during WWII.

Tori investigate the remains of children and teenagers found in Leeds city centre. The team reveals what life was like for the children of the Industrial Revolution.

Annually, Illinois gets more than 300 UFO reports, so why are the Tinley Park sightings - with over 70 witnesses each year - the only reports that happen en masse.

Fall of Berlin: Survivors recount the horrors behind surviving a merciless place and hear the shock as they discover the evil secret of Germany's concentration camps.

Final Victory: The war in the Pacific nears its violent end as a drastic tactic triggers the nuclear age. The brave men share their thoughts on the war's most tragic events.

Experts investigate the 'greys' - mysterious beings with big heads and eyes found carved into rocks. Who are these strange figures and what inspired them.

Did Mother Nature cause the volcanoes, earthquakes and floods of ancient times? Or could aliens have been responsible? Experts investigate.

In 1923, Adolf Hitler led the infamous Beer Hall Putsch, an attempt to take power in Germany by force. It was a day that would change the world forever, birthing Hitler's regime.

The Seeds of Violence 1918-1922: In the wake of the First World War, Adolf Hitler identifies Benito Mussolini as his model and has one ultimate goal: to gain power in Germany.

Chicago: Craig and Sarah take on the Chicago O'Hare case of November 2006, a mass sighting of a flying saucer hovering over a United Airlines airport gate.

A look at the CIA's rumoured investment in psychological operations. Could there be an army of remote viewers watching American citizens today.

On 8 April 2011, the FBI declassified decades of top secret government documents for the first time. Here, experts examine the possibility of the end of the world.

At the midway stage of the competition, each competitor is tasked with creating a glass art centrepiece fit for a dining room table.

The stakes are raised as the final comes into view on the horizon. This episode sees the competitors design a perfume bottle with a sculpted stopper.

It was mankind's finest hour, the greatest technological achievement of the 20th century - the Apollo 11 mission to the Moon.

Do India's Sanskrit texts, with their descriptions of advanced technology, lend themselves to the theory that aliens once walked amongst us.

Up in Flames 1936-1940: At the end of 1939, the German Army invades Poland. Examine how Hitler succeeded in pushing through his rearmament and war plans relatively unhindered.

With the Allies at crisis point, pressure mounts on the Wrens to prove their worth and the stage is set for a battle that will turn the tide of the Atlantic war.

Capture of a key Nazi uncovers shocking realities. Amid demands for accountability, as Vera and her team navigate murky waters to confront uncomfortable truths.

It was mankind's finest hour, the greatest technological achievement of the 20th century - the Apollo 11 mission to the Moon.

Do India's Sanskrit texts, with their descriptions of advanced technology, lend themselves to the theory that aliens once walked amongst us.

Travelling east, Alice discovers a Roman barn conversion, unearthing a Tudor fort and finding intricately carved 10,000-year-old weapons.

Alice investigates an Ice Age camp, the mystery of a medieval skeleton and the earliest evidence of salt making in Britain.

Digs in northern Britain reveal a Roman emperor's lost bathhouse and a formidable fortress perched on top of a Scottish mountain.

Dr Alice Roberts examines an RAF air base with a Roman past and a pub with a very long history of hospitality in central England.

Alice explores the West of Britain, where some castles stand tall, while others have almost disappeared into the landscape.

Dive into a video from the US Navy that proves once and for all that UFOs exist and examine an alleged Loch Ness monster sighting.

With the Allies at crisis point, pressure mounts on the Wrens to prove their worth and the stage is set for a battle that will turn the tide of the Atlantic war.

When humanity disappears, the global retail machine collapses. Malls rot and grocery stores become battlefields for rodents.

Did a Las Vegas family have a close encounter with ten-foot-tall aliens in their backyard.

A leopard goes on a rampage, a paraglider plummets to earth and a woman gets too close to an elephant.

It was mankind's finest hour, the greatest technological achievement of the 20th century - the Apollo 11 mission to the Moon.

Do India's Sanskrit texts, with their descriptions of advanced technology, lend themselves to the theory that aliens once walked amongst us.

The Mystery of Puma Punku. Experts in the extra-terrestrial examine the Inca ruin and its mysteriously intricate carved blocks.

Hugh and the team uncover a World War Two prisoner of war camp beneath a housing estate in Oldham. Glen Mill held over six thousand enemy prisoners.

Travelling east, Alice discovers a Roman barn conversion, unearthing a Tudor fort and finding intricately carved 10,000-year-old weapons.

Dive into mystery: a sunken Italian city, a Keys underwater cemetery, a South Pacific yellow brick road and strange rocks off Australia.

The guys are in British Columbia, where they're ready to blow a big wad of cash on a few West Coast treasures.

Russia spans over six million square miles of some of the most rugged terrain on Earth, much of which is uninhabited and largely unexplored.

Going by ancient cultures' depictions of gods appearing as animals, could it be that extraterrestrials bear more resemblance to animals than humans.

The Gates of Hell 1941-1942: In the shadow of the war, the Nazi regime gradually advances its "final solution to the Jewish problem", culminating in the Holocaust.

The battle hits a turning point and Donitz unleashes an advanced torpedo to flip the momentum. Roberts and Laidlaw must devise a strategy to combat the new threat.

Uncover some of the world's most renowned encryptions, revealing how they were decoded, the minds who cracked them and the secrets they masked.

Russia spans over six million square miles of some of the most rugged terrain on Earth, much of which is uninhabited and largely unexplored.

Going by ancient cultures' depictions of gods appearing as animals, could it be that extraterrestrials bear more resemblance to animals than humans.

Explore the men in charge whose rampant egos and misguided belief in their own abilities led to their country making fatal mistakes in the war.

Explore how the seeds of Japan's defeat in 1945 were sown a decade earlier with the occupation of Manchuria in China.

Explore how the Axis Powers' ruthless, brutal occupation and exploitation of other countries contributed to their demise.

Victory in war doesn't just require sound military strategy, vital resources and equipment are also critical. Discover how the Axis powers failed in this regard.

In our final episode, we examine how each Axis Power had troubles on their own home front, leading to disaster in the final days of the war.

Witness supposed video evidence of a UFO over Houston, a creature in an attic and a sighting of Bigfoot in Utah.

The battle hits a turning point and Donitz unleashes an advanced torpedo to flip the momentum. Roberts and Laidlaw must devise a strategy to combat the new threat.

Uncover some of the world's most renowned encryptions, revealing how they were decoded, the minds who cracked them and the secrets they masked.

Experts reveal the highly encrypted phones that criminal gangs use to stay under the radar, and explain how the police are turning the phones against the crooks.

At Mexico City's Templo Mayor, archaeologists uncover a 15th-century tower of 600 skulls, revealing new insights into Aztec sacrifice and ritual.

Russia spans over six million square miles of some of the most rugged terrain on Earth, much of which is uninhabited and largely unexplored.

Going by ancient cultures' depictions of gods appearing as animals, could it be that extraterrestrials bear more resemblance to animals than humans.

Alien Messages: Could some of our ancient texts and structures be home to secret messages left by alien ancestors? If so, what can we learn from them.

Hugh and the team solve a 17th-century mystery in King's Lynn as they hunt for defensive earthworks from the English Civil War.

Alice investigates an Ice Age camp, the mystery of a medieval skeleton and the earliest evidence of salt making in Britain.

Explore a psychedelic swirl in the Utah wastelands, a bizarre configuration of circles in the Sahara and a remote polka-dot lake in Canada.

There's fertile picking in the Fraser Valley when the guys stop in to scour a hangar-sized collection of Canadiana.

The US military has denied that the 1947 Roswell crash was anything other than a weather balloon, but FBI files include a memo that indicate otherwise.

While many believe in reincarnation, experts suggest that extraterrestrials designed the human body to be a vessel for otherworldly beings.

Genocide 1942-1944: Along with Treblinka and Majdanek, Sobibor was one of the camps used in Operation Reinhard, in which the Nazis murdered almost two million people.

Small arms production hit a boom in the early 1800s with the emergence of the modern cartridge; an invention that led to the lethal package.

The Zodiac Killer Code reveals the desperate bid to crack the crazed codes sent by America's most mysterious serial killer.

The US military has denied that the 1947 Roswell crash was anything other than a weather balloon, but FBI files include a memo that indicate otherwise.

While many believe in reincarnation, experts suggest that extraterrestrials designed the human body to be a vessel for otherworldly beings.

Experts explore the similarities between huge pyramids across the world. Could extraterrestrials have influenced their construction and design.

Ancient astronaut theorists hunt for evidence linking Bigfoot to alien species from the distant past. Could the ape-like giant be an extraterrestrial.

Ancient astronaut experts believe the minds of Einstein and Galileo were superhuman. Could these historical geniuses have had extraterrestrial connections.

In 1980, a man received a code after touching an alleged spaceship. After the sequence was translated, he was told never to speak of the incident again.

Ancient alien theorists ask whether the Greeks and Egyptians understood electricity. Could extraterrestrials have introduced them to such technology.

What's the truth behind the Chupacabra sighting? Is this the greatest UFO photo taken? What are those sounds on Mars.

Small arms production hit a boom in the early 1800s with the emergence of the modern cartridge; an invention that led to the lethal package.

The Zodiac Killer Code reveals the desperate bid to crack the crazed codes sent by America's most mysterious serial killer.

Science shines a light on the dark side of Ancient Egypt, from a 5,000-year-old homicide to drug-fuelled debauchery - and one very shocking revelation.

Explore the truth and lies behind ancient Egypt's best known and loved icons, including the Great Sphinx, Tutankhamun and more.