Michael Asher attempts to unravel the mystery behind the death of Hanning Speke, the man who, with Richard Burton, claimed to have found the source of the Nile. 1/6.
Divers find the wreck of a German U-Boat off the coast of New Jersey, USA. The records say it shouldn't be there. Three lives are lost in solving the mystery.
London students put theories about eco-tourism into practice in the heart of the Amazonian jungle.
What's reputed to have been the largest meteorite to bounce against our planet is thought to have landed in the Sahara in 1916. Slivers of it have emerged from collectors but scientists are still searching for the slivers' Big Daddy which, it's thought,is out there among the dunes.
The documentary adventure series ends with the work of salvage master Arjen Hoekstra and his team who have to save an abandoned container ship before its lethal cargo explodes.