TV Guide for Tomorrow Wednesday 26 in Sky History 2

Experts scrutinise prehistoric ruins, asking whether humans could have built these advanced structures alone. Might they have had alien help.

Few have ever heard of the top-secret base in the deserts of Utah known as Area 52, but reports of UFOs have convinced people that the US military is keeping secrets.

Sharp Top Mountain B-25 Crash: Garth Barnard investigates World War II air accidents, starting with a B-25 training crash in Virginia that killed five crew.

Explore the complex case of the death of Wladyslaw Sikorski, the Polish PM whose plane crashed soon after taking off in 1943.

Australia's Worst Crash: Australia's worst aviation accident happened in 1943 when 40 crew died in a B-17 bomber crash.

Drug dealer Dale Cregan hit the headlines in 2012 when he murdered police officers Nicola Hughes and Fiona Bone. Dermot Murnaghan examines the tragic case.

Experts question whether the truth of our alien past could be buried in areas that, due to warfare or instability, are off-limits to exploration.

Ancient alien theorists explore the origins of mythical gods. Could these tales of superhuman beings be based on sightings of extraterrestrials.

Declassified records reveal elite forces' extreme missions, from deep-sea divers on Soviet cables to A-bomb deployments in hostile zones.

Experts explore how the ambush has revolutionised warfare with the benefit of undetected weapons, from the caltrop to the insidious land mine.

A look at the horrific crimes of Angus Sinclair, who murdered two teenage girls in Edinburgh in October 1977. Dermot Murnaghan presents.

Experts question whether the truth of our alien past could be buried in areas that, due to warfare or instability, are off-limits to exploration.

Ancient alien theorists explore the origins of mythical gods. Could these tales of superhuman beings be based on sightings of extraterrestrials.

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

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

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

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

Experts in the extra-terrestrial examine the Inca ruin and its mysteriously intricate carved blocks.

Discover South Korea's seaweed farms, visit an Alaskan town where everyone lives under one roof and check out a flooded passage that leads to the French island of Noirmoutier.

For decades, extraterrestrial research has been directed to the skies - but researchers believe that UFOs may also be inhabiting our oceans.

Experts explore how the ambush has revolutionised warfare with the benefit of undetected weapons, from the caltrop to the insidious land mine.

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.

With an empire ripped apart by civil war, Rome welcomes an extraordinary new emperor: Aurelian, rising from the rank of soldier to fight for his city.

Experts study previous reports of zombies, vampires and spirits. Could these sightings of the undead actually have been alien encounters.

For decades, extraterrestrial research has been directed to the skies - but researchers believe that UFOs may also be inhabiting our oceans.

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

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