Scapa Flow lies barely seven degrees below the Arctic Circle, in the cold, windswept Orkney Islands at the northern tip of Scotland. Measuring 10 kilometres wide by 8 kilometres long with an average depth of 30 metres, this natural anchorage is bounded to the north by the mainland, to the east by the islands of Burray and South Ronaldsay, and to the west by the island of Hoy. In 1904, Scapa Flow was chosen as the home base for the British Grand Fleet, allowing the Royal Navy and German Imperial Navy to glower at each other across the North Sea. It was from here that the Grand Fleet sailed to the historic 1916 Battle of Jutland, and to here that the German High Seas Fleet sailed to surrender in 1918. In the years leading up to the Second World War, Scapa Flow was thought to be impregnable, and came to symbolize the supposed invincibility of the Royal Navy itself. But in the early morning hours of October 14, 1939, a lone German U-boat succeeded in doing the impossible, penetrating the harbour’s defences, sinking a 30,000-ton battleship, and slipping away undetected. It was one of the most daring feats of the war, and one which shattered the Royal Navy’s illusion of invulnerability. This is the incredible story of the U-47 and Captain Günther Prien, “The Bull of Scapa Flow.” Author: Gilles Messier Editor: Daven Hiskey Host: Simon Whistler Producer: Samuel Avila Learn more about your ad choices. Visit megaphone.fm/adchoices