Dan Snow investigates the history of WWII in Northern Ireland. He learns the story of the most successful U-boat hunter of all time, and dives to the wreck of the famed U-155.

Dan Snow uncovers the history of WWII in Northern Ireland. He learns the story of the Empire Heritage, a cargo ship that was sunk off Malin Head during the Battle of the Atlantic.

Dan Snow uncovers the history of WWII in Northern Ireland. He travels to RAF Cluntoe where crew were trained to fly missions, and reveals how the Battle of the Atlantic ended.