Time Travellers: Scientists explore the possibility that sightings of alien beings or UFOs may be evidence of time travellers from the future. (S4, ep 12).

Tunneling to Freedom: A daring prison break, engineered by former teacher Colonel Thomas Rose, frees hundreds of captured Union soldiers during the Civil War. (S2, ep 7).

Romans: Silchester is one of the best preserved Roman sites in Britain. Why did Rome's infamous emperor Nero stamp his mark on the town? (S2, ep 2).

Cold War Warriors: Exploring the Cold War vessels that played pivotal roles in events such as the blockade of Cuba and the Vietnam war. (S1, ep 6).

The Da Vinci Conspiracy: Experts scrutinise the paintings, journals and technical drawings of Leonardo Da Vinci. Could they hide evidence of extra-terrestrial beings? (S4, ep 11).

Time Travellers: Scientists explore the possibility that sightings of alien beings or UFOs may be evidence of time travellers from the future. (S4, ep 12).

Breakout in Plain Sight: An Iranian-American psychopath goes to jail in Southern California, but escapes before he can be transferred to a higher security prison. (S2, ep 8).

Invincible: For more than 260 years, HMS Invincible lay at the bottom of the Solent. Now, archaeologists are diving beneath the waves to learn more about this game-changing ship. (S2, ep 3).

D-Day In The Pacific: 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. (S1, ep 8).

Carl Wark - Saxon Frontier Fortress: The team investigates the origins of a hill fort situated on Hathersage Moor in the Peak District. (S3, ep 6).

Atlantis: Legend has it that this ancient civilisation was wiped out by a volcanic eruption, but could the discovery of spectacular palaces in Crete and Santorini challenge the theory.

Skyfall: Exploring why the Celts moved from prosperous cities into smaller fortified settlements and how this triggered their decline in Central Europe. (3 of 3).

The Cave to Hell: Discover images of an Iceland cave that could hold alien secrets, military structures in the Utah desert and a bloody stain in the sands of Saudi Arabia. (S6, ep 5).

Time Travellers: Scientists explore the possibility that sightings of alien beings or UFOs may be evidence of time travellers from the future. (S4, ep 12).

Inside the Tower of London: A look at an extraordinary display of nearly 900,000 ceramic poppies in the moat. Also, Curator Bridget explores a reminder of the horrors of war. (S1, ep 3).

Dawn of the Animated Blockbuster: Facing soaring costs, mounting criticism and a tight deadline, Walt Disney creates the first full-length animated feature film. (S1, ep 2).

The Tudors: Amanda explores the feisty affair between Henry VIII and Anne Boleyn, showing how her sexual control ended in disaster. Meanwhile, Dan learns to joust. (S1, ep 2).

The Da Vinci Conspiracy: Experts scrutinise the paintings, journals and technical drawings of Leonardo Da Vinci. Could they hide evidence of extra-terrestrial beings? (S4, ep 11).

Time Travellers: Scientists explore the possibility that sightings of alien beings or UFOs may be evidence of time travellers from the future. (S4, ep 12).

Dawn of the Animated Blockbuster: Facing soaring costs, mounting criticism and a tight deadline, Walt Disney creates the first full-length animated feature film. (S1, ep 2).

D-Day In The Pacific: 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. (S1, ep 8).

Carl Wark - Saxon Frontier Fortress: The team investigates the origins of a hill fort situated on Hathersage Moor in the Peak District. (S3, ep 6).

Atlantis: Legend has it that this ancient civilisation was wiped out by a volcanic eruption, but could the discovery of spectacular palaces in Crete and Santorini challenge the theory.

The Ultimate Guide To UFOs: UFO witnesses have reported a variety of objects in Earth's skies for centuries - could they offer clues about more intelligent life in our galaxy? (S12, ep 32).

Aliens And The Presidents: The White House has consistently denied any knowledge of aliens, but is it in fact possible that extraterrestrials have been influencing presidents? (S12, ep 33).

The Divine Number: What is it about the number 12? It holds divine significance in numerous sacred traditions and it's found repeatedly in ancient architecture. But why? (S12, ep 35).

Plantagenet Canterbury: Alice studies the history of Canterbury, learning the true horror of the Black Death and exploring the iconic cathedral. (5 of 6).

Glasgow Age of Steam: Alice Roberts explores Glasgow's age of steam, from lethal diseases and industrial injury to genteel tea rooms. (S3, ep 5).

East: Alice Roberts and Matt Williams present more outstanding archaeology. In the east of Britain, sites include Must Farm, Colchester, Oakington, Lyminge and Silchester. (S3, ep 1).

West: Alice Roberts and Matt Williams visit the Dorset Country Museum, where they explore finds from archaeological digs across the west of Britain. (S3, ep 2).

Vindolanda And WWII Spitfire: The team search for remains of the crashed WWII Spitfire and discover parts of the cockpit. (1 of 4).

Medieval Mystery: Did our ancestors believe they were cursed? Professor Alice Roberts explores historic cataclysmic events such as wars and floods to dispel the myths. (5 of 5).

Regency Cheltenham: Alice studies the history of Cheltenham, Britain's most Regency town. She attends a period society ball, investigates the rigid social hierarchy and more. (5 of 6).

Plantagenet Canterbury: Alice studies the history of Canterbury, learning the true horror of the Black Death and exploring the iconic cathedral. (5 of 6).

Glasgow Age of Steam: Alice Roberts explores Glasgow's age of steam, from lethal diseases and industrial injury to genteel tea rooms. (S3, ep 5).

East: Alice Roberts and Matt Williams present more outstanding archaeology. In the east of Britain, sites include Must Farm, Colchester, Oakington, Lyminge and Silchester. (S3, ep 1).

West: Alice Roberts and Matt Williams visit the Dorset Country Museum, where they explore finds from archaeological digs across the west of Britain. (S3, ep 2).

Vindolanda And WWII Spitfire: The team search for remains of the crashed WWII Spitfire and discover parts of the cockpit. (1 of 4).

Henry IV: The Usurper: Best known for usurping and murdering his cousin, Henry IV suffered from a mysterious debilitating skin condition during the later years of his reign. (S2, ep 3).

The Missing Jackson Letter: Taylor unearths new testimony from a witness to Slumach's execution and a deathbed letter sends Adam and Kru on a dangerous glacial trek. (S1, ep 1).

Festive Fugitives: Six inmates smash a rusted toilet through a bathroom wall in six minutes in order to escape on a Christmas night in Tennessee. (S1, ep 5).

The Ultimate Guide To UFOs: UFO witnesses have reported a variety of objects in Earth's skies for centuries - could they offer clues about more intelligent life in our galaxy? (S12, ep 32).

Aliens And The Presidents: The White House has consistently denied any knowledge of aliens, but is it in fact possible that extraterrestrials have been influencing presidents? (S12, ep 33).

The Divine Number: What is it about the number 12? It holds divine significance in numerous sacred traditions and it's found repeatedly in ancient architecture. But why? (S12, ep 35).

Henry IV: The Usurper: Best known for usurping and murdering his cousin, Henry IV suffered from a mysterious debilitating skin condition during the later years of his reign. (S2, ep 3).

Inside the Tower of London: A look at an extraordinary display of nearly 900,000 ceramic poppies in the moat. Also, Curator Bridget explores a reminder of the horrors of war. (S1, ep 3).

The Cave to Hell: Discover images of an Iceland cave that could hold alien secrets, military structures in the Utah desert and a bloody stain in the sands of Saudi Arabia. (S6, ep 5).

The Lost Kingdom: According to the earliest Tibetan traditions, hidden in the Himalaya Mountains is Shambhala, a kingdom of the gods. Does this mystical realm truly exist? (S12, ep 36).

The Forbidden Bible: An exploration of the possibility that The Book of Enoch was stricken from the Bible because it documents humanity's extraterrestrial origins. (S12, ep 37).

The Galactic Keyhole: The mysterious keyhole symbol exists in mystic texts, sacred architecture and artwork found around the globe. Is there more to it than meets the eye? (S12, ep 38).

Stewart Sturling: Alice explores the story of Stewart Britain by visiting the home of the Scottish royals who eventually took the English throne in 1603 and created Great Britain. (6 of 6).

Georgian Edinburgh: Alice Roberts explores Georgian Edinburgh's finest architecture, the roots of modern Scottishness, and some dark imperial controversies. (S3, ep 6).

North: Alice Roberts and Matt Williams visit the Neolithic Orkney World Heritage Site, where they explore finds from archaeological digs across the north of Britain. (S3, ep 3).

Stone Age Engineering and Battle of Bullecourt: Finds from the East include a monument as old as Stonehenge and some disturbing Roman burials. (3 of 4).

Roman Bathhouse and Hessian Camp: Alice Roberts shares archaeological discoveries from the west of the UK, including a Roman bath house and a German camp. (2 of 4).

Ancient Global Warming: Did our ancestors believe they were cursed? Professor Alice Roberts explores historic cataclysmic events such as wars and floods to dispel the myths. (1 of 5).

Victorian Belfast: Alice reveals the history of Belfast, the UK's most Victorian city. She visits the shipyards that built the Titanic and gets locked up in the Crumlin Road gaol. (6 of 6).

Stewart Sturling: Alice explores the story of Stewart Britain by visiting the home of the Scottish royals who eventually took the English throne in 1603 and created Great Britain. (6 of 6).

Georgian Edinburgh: Alice Roberts explores Georgian Edinburgh's finest architecture, the roots of modern Scottishness, and some dark imperial controversies. (S3, ep 6).

North: Alice Roberts and Matt Williams visit the Neolithic Orkney World Heritage Site, where they explore finds from archaeological digs across the north of Britain. (S3, ep 3).

Stone Age Engineering and Battle of Bullecourt: Finds from the East include a monument as old as Stonehenge and some disturbing Roman burials. (3 of 4).

Roman Bathhouse and Hessian Camp: Alice Roberts shares archaeological discoveries from the west of the UK, including a Roman bath house and a German camp. (2 of 4).

Anne: The Forgotten Queen: Professor Alice Roberts delves into the life and death of Anne, Queen of England from 1702-1714, who shockingly endured 17 failed pregnancies. (S2, ep 4).

Royalty: In the early 20th century, the British royal family fought for popularity. Rare film, seen in colour for the first time, tells the story of how they managed to survive. (S1, ep 1).

A hitchhiker is terrified when lights appear to attack him. A sighting in France becomes one of the most investigated cases in UFO history. (S2, ep 12).

In Nova Scotia, a former naval officer sees five bright lights in the skies and a cigar-shaped object behind them.

According to the earliest Tibetan traditions, hidden in the Himalaya Mountains is Shambhala, a kingdom of the gods. Does this mystical realm truly exist.

An exploration of the possibility that The Book of Enoch was stricken from the Bible because it documents humanity's extraterrestrial origins.

The mysterious keyhole symbol exists in mystic texts, sacred architecture and artwork found around the globe. Is there more to it than meets the eye.

In the early 20th century, the British royal family fought for popularity. Rare film, seen in colour for the first time, tells the story of how they managed to survive.

The Forgotten Queen: Professor Alice Roberts delves into the life and death of Anne, Queen of England from 1702-1714, who shockingly endured 17 failed pregnancies.

Wales: Craig Charles joins forces with world-renowned space journalist Sarah Cruddas to investigate some of the most perplexing UFO encounters of recent times.

Theorists investigate a depiction of a stegosaurus found at Angkor Wat in Cambodia. Could it suggest that alien species killed off the dinosaurs.

No one knows who designed and built Bolivia's sophisticated temple complex. Could it have been aliens? Experts investigate.

An Iranian-American psychopath goes to jail in Southern California, but escapes before he can be transferred to a higher security prison.

For more than 260 years, HMS Invincible lay at the bottom of the Solent. Now, archaeologists are diving beneath the waves to learn more about this game-changing ship.

Stories of hospital ships and those who served on them, including the tragic story of the sinking of the Titanic's sister vessel, The Britannic.

Theorists investigate a depiction of a stegosaurus found at Angkor Wat in Cambodia. Could it suggest that alien species killed off the dinosaurs.

No one knows who designed and built Bolivia's sophisticated temple complex. Could it have been aliens? Experts investigate.

The SS Normandie entered service in 1935 and remains the most powerful steam turbo-electric-propelled passenger ship ever built.

Archaeologists conduct a dig at Auckland Castle in Co Durham, which 700 years ago was home to a group of power-crazed bishops.

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

On its 200th anniversary, a team of experts uncover hidden mysteries of the Battle of Waterloo - one of the greatest and bloodiest battles ever fought.

St Paul laid the foundations for what became Christianity. He shaped our world. Now, using the latest research and CGI, see the world that created him.

February 1942, and the sky over Los Angeles erupts as anti-aircraft guns begin firing on strange targets. Could this have been an extraterrestrial raid.

Discover a trail of moving objects in the ice of Antarctica, evidence of one of Joseph Stalin's most insane schemes and a code in the Sonoran Desert.

Allen and Ton uncover an 1886 rifle invented to kill buffalo. Then they head to the monster track to test 1950s electric slot cars.

Allen and Ton come up against Texas's most elite buyers as they discover a military-grade cruise missile jet engine and a Wild West saddle.

Ireland: Craig Charles joins forces with world-renowned space journalist Sarah Cruddas to investigate some of the most perplexing UFO encounters of recent times.

The Vikings: Comedian John Thomson and historian Janina Ramirez join Al to explore the truth about Vikings and how they were so successful in Britain.

Divers probe the depths of the North Pacific, where the world's largest known species of octopus lives.

Theorists investigate a depiction of a stegosaurus found at Angkor Wat in Cambodia. Could it suggest that alien species killed off the dinosaurs.

No one knows who designed and built Bolivia's sophisticated temple complex. Could it have been aliens? Experts investigate.

An Iranian-American psychopath goes to jail in Southern California, but escapes before he can be transferred to a higher security prison.

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

On its 200th anniversary, a team of experts uncover hidden mysteries of the Battle of Waterloo - one of the greatest and bloodiest battles ever fought.

St Paul laid the foundations for what became Christianity. He shaped our world. Now, using the latest research and CGI, see the world that created him.

Experts question ancient civilisations' fixation with the Orion constellation. Could this star group have been an entry point for aliens visiting Earth.

Experts question the startling similarities in burial tombs from distant cultures, asking if aliens could have influenced their complicated designs.

The SS Normandie entered service in 1935 and remains the most powerful steam turbo-electric-propelled passenger ship ever built.

Archaeologists conduct a dig at Auckland Castle in Co Durham, which 700 years ago was home to a group of power-crazed bishops.

Ships don't have to be large to make history, like the 1776 gunboat built to stop a British invasion, or the remarkable story of the HA-19 sub.

Experts question ancient civilisations' fixation with the Orion constellation. Could this star group have been an entry point for aliens visiting Earth.

Experts question the startling similarities in burial tombs from distant cultures, asking if aliens could have influenced their complicated designs.

Renowned for its sheer power, the awe-inspiring Queen Elizabeth is the Royal Navy's lead ship and largest ever constructed.

The team search for artefacts from the country's first superhighway - the Bridgewater Canal.

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

The Pyramids of Giza are the only surviving wonder of the ancient world, becoming a UNESCO World Heritage Site in 1979. But what truths are they hiding.

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

During the Cold War, strange lights and unidentified objects put governments around the world on red alert. Could extra-terrestrials have been responsible.

A strange structure discovered in the Gobi Desert could reveal the whereabouts of lost treasure - changing everything we know about Genghis Khan.

Visit ancient architectural wonders and investigate how the Persians, Egyptians, Greeks and Romans accomplished their design and constructions without modern tools.

Fritz Todt was the man tasked with engineering projects including the autobahn, the West Wall defences and more. But in 1942, he died under mysterious circumstances.

US: Ross Kemp heads to New York, discovering the connection between USA and Britain in the rise of the mafia - as well as learning about the infamous Kray twins.

Surveillance footage from China records a man surviving a lightning strike, not once but twice. In a remote valley in Norway, cameras track mysterious lights.

Experts question ancient civilisations' fixation with the Orion constellation. Could this star group have been an entry point for aliens visiting Earth.

Experts question the startling similarities in burial tombs from distant cultures, asking if aliens could have influenced their complicated designs.

Visit ancient architectural wonders and investigate how the Persians, Egyptians, Greeks and Romans accomplished their design and constructions without modern tools.

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

The Pyramids of Giza are the only surviving wonder of the ancient world, becoming a UNESCO World Heritage Site in 1979. But what truths are they hiding.

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

Did prophets such as Elijah and Joseph Smith communicate with a heavenly source or did they actually come into contact with extraterrestrials.

Ancient alien theorists explore the mysterious phenomena of the Nazca Lines. Could these huge geoglyphs in Southern Peru have an extraterrestrial connection.

Renowned for its sheer power, the awe-inspiring Queen Elizabeth is the Royal Navy's lead ship and largest ever constructed.

The team search for artefacts from the country's first superhighway - the Bridgewater Canal.

We learn about life on a Tudor ship from objects found on the Mary Rose, while on HMS Victory we learn the battle-winning tactics of Admiral Nelson.

Did prophets such as Elijah and Joseph Smith communicate with a heavenly source or did they actually come into contact with extraterrestrials.

Ancient alien theorists explore the mysterious phenomena of the Nazca Lines. Could these huge geoglyphs in Southern Peru have an extraterrestrial connection.

Lacking in speed and might, the SS Andrea Doria more than made up for it in beauty, but on the night of 25 July 1956 - the Italian liner met a disastrous fate.

Uncovering the stories behind a Yorkshire garrison's stables and the horse the Germans could not kill.

The team explore mystery cults and ancient catacombs to determine whether it's possible that the Ark of the Covenant was stolen and hidden in Rome.

For centuries, the Holy Grail has been an object of mystery and fascination, with ties to the Last Supper and the crucifixion of Jesus Christ.

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

A look at some of the most widely witnessed UFO events ever, including large black triangular objects in the night sky regularly spotted in the 80s and 90s.

When a strange plane is discovered near the sight of the Roswell UFO incident, experts wonder if the aircraft has Nazi or extraterrestrial origins.

A German-American pilot, Dieter Dengler, uses survival skills honed as a child to escape a secret prison in Laos during the early years of the Vietnam war.

William Shatner is back on the hunt to find answers to the unexplainable, this week focussing on the red planet, Mars.

Mysterious industrial waste is discovered in an uninhabited part of Greenland. Meanwhile, strange mounds are found deep within the Arctic Circle.