Edge West Productions

They are striking works of art by any standard: but what purpose did they serve? Some of the theories put forward suggest that the lines were ancient running tracks, runways for aliens, and even a giant astronomical calculator. But after decades of misunderstanding, modern archaeology may finally have an answer to the puzzle of the Nasca lines.

Over the centuries, explorers traded tales of a lost civilization amid the dense Amazonian rainforest. Scientists dismissed the legends as exaggerations, believing that the rainforest could not sustain such a huge population—until now. A new generation of explorers armed with 21st-century technology has uncovered remarkable evidence that could reinvent our understanding of the Amazon and the indigenous peoples who lived there. Using CGI and dramatic re-creations, National Geographic re-imagines the banks of the Amazon 500 years ago, teeming with inhabitants living in the Lost Cities of the Amazon.

On the eve of Thanksgiving, 1971 a man, dressed in a business suit, leaps out of the back of a commercial jet with a parachute and two hundred thousand dollars in ransom money. Now for the first time in FBI history a team of citizen sleuths, using modern forensic science, is helping unravel the mystery of D.B. Cooper.

Behind the high-tech offices and employees lurks Japan's Yakuza, killing, stealing and extorting.

An insight into Frank Lee Morris and brothers John and Clarence Anglin's 1962 attempt to escape from Alcatraz, reputedly the world's most secure prison at the time. The authorities always maintained the prisoners drowned, but the programme examines evidence suggesting at least one of them reached the mainland.