Historical documentary which explores the efforts of German soldiers during World War II.
The outbreak of the Second World War meant that both sides had to concentrate a huge amount of their workforce on rearmament, with large amounts of supplies being delivered by air.
The German army relied heavily on their U-boats, and with ambush tactics devised by their creator, Admiral Doentitz, they became a dangerous force on the water.
The programme includes rare footage of former captains and U-boats in action.