NARRATOR:For 40 years, a fossil skull discovered in Piltdown, a quaint village in England, was hailed as the missing link between apes and humans. It was named Piltdown Man. Later it would be called a forgery and set off a storm of scandal... ANDY CURRANT (Natural History Museum, London):It's a vicious hoax. It was a terrible thing to do. It really was a horrible, nasty, vicious piece of work. NARRATOR:....the identity of the Piltdown hoaxer has remained a mystery. With special access to Britain's Natural History Museum archives, NOVA reopens the case and reveals hints of a cover up at...