Explorer Season 6, Episode 5: Nazi Mystery: Twins from Brazil

Mystery of The Disembodied Feet

Inside LSD

Secret History of Diamonds

24 Hours After Asteroid Impact

25 Years

Journey to an Alien Moon

Fatal Insomnia

An extremely rare genetic disease passed down through generations, fatal familial insomnia's (FFI) primary symptom is sleeplessness, but with a fatal twist: victims are dead within months. National Geographic delves into the science of sleep to find out why we need sleep and what happens to us when we don't get it. Witness the pioneering research inside the sleeping brain as well as the mind forbidden to rest for days at a time.

Talibanistan

Electronic Armageddon

Inside the DEA

24 Hours After Hiroshima

Albino Murders

Inside Bioterror

Can the Gulf Survive?

Lost Mummies of New Guinea

How Man Tamed the Wild

Born to Rage?

American Hostage

Lost Cannibals of Europe

How to Build a Beating Heart

Clash of the Americas

Finding the Lost da Vinci

Leonardo da Vinci's "The Battle of Anghiari" vanished 500 years ago, with only copies rendered by other artists left behind to confirm its existence. Scientist and art enthusiast Maurizio Seracini, has dedicated 36 years to tracking down the missing mural, and seems to be on the verge of uncovering the hidden fresco behind the walls of the Palazzo Vecchio in Florence, Italy.

The Man Who Can Fly

Fighting ISIS

National Geographic writer Neil Shea travels to the heart of Kurdistan on a quest to meet the Kurdish fighters on the front lines against the world's biggest terrorist threat, ISIS.