During World War II, Germany's U-Boat fleet fought a deadly game of cat-and-mouse with the Allies for control of the Atlantic.

The two-part series joins a team of divers and historians as they explore the U-Boat wrecks, which have remained forgotten, and untouched, for nearly 70 years. Along the way the series tells the full story of the U-Boat war - the key events, the heroes and villains, and the changing tide of technological advances using motion graphics, moving first hand testimony and detailed expert analysis.

As seen in Australia on SBS.