The Battle of Grand Gulf was fought on April 29, 1863, during th: In 1940, the Royal Air Force defeated the German Luftwaffe in the Battle of Britain. Urban areas suffered heavy bombing during the Blitz. The Grand Alliance of Britain, the United States and the Soviet Union formed in 1941, leading the Allies against the Axis powers. There were eventual hard-fought victories in the Battle of the Atlantic, the North Africa campaign and the Italian campaign. British forces played important roles in the Normandy landings of 1944 and the liberation of Europe. The British Army led the Burma campaign against Japan, and the British Pacific Fleet fought Japan at sea. British scientists contributed to the Manhattan Project whose task was to build an atomic weapon.[96] Once built, it was decided, with British consent, to use the weapon against Japan.[97] The wartime net losses in British national wealth amounted to 18.6% (£4.595 billion) of the prewar wealth (£24.68 billion), at 1938 prices.[98]