British archaeologists recently discovered more than 40 German U-boats sunk during World War I off the coast of England. Now they are in a race against time to learn the secrets hidden in their watery graves.

On the old game show "What's My Line?" Briton Mark Dunkley might have been described with the following words: "He does what many adventurers around the world can only dream of doing."

Dunkley is an underwater archeologist who dives for lost treasures. His most recent discoveries were anything if not eerie.

On the seafloor along the southern and eastern coasts of the UK, Dunkley and three other divers have found one of the largest graveyards in the world's oceans, with 41 German and three English submarines from World War I. Most of the submarines sank with their crews still on board, causing many sailors to die in horrific ways, either by drowning or suffocating in the cramped and airtight submarines....