The bodies of three men and two children have been found entombed in a cave in one of the most inhospitable places on earth, the edge of Bolivia 's vast salt plain - the Salar de Uyuni. James and Tiffiny discover that at least three of the skeletons show signs of blows to the head powerful enough to kill them. Is this a case of piracy on the salt plain? Human sacrifice? Or possibly even both? In Part 2: London 's Greenwich Naval Hospital , used from 1750 to 1840 for retired sailors, was the resting place of some 20,000 souls - vital skeleton clues to life in the ...