As the German army advances through northern France during the early days of World War II, it cuts off British troops from their French allies, forcing an enormous evacuation of soldiers across the North Sea from the town of Dunkirk to England. The Allied armies, trapped by the sea, were quickly being encircled on all sides by the Germans. By May 19, 1940, British commanders were already considering the withdrawal of the entire British Expeditionary Force (BEF) by sea. On May 26, the British began to implement Operation Dynamo—the evacuation of Allied forces from Dunkirk. As there were not enough ships to transport the huge masses of men stranded near the beaches, the British Admiralty called on all British citizens in possession of any seaworthy vessels to lend their ships to the effort. Hundreds of fishing boats, pleasure yachts, lifeboats, ferries and other civilian ships of every size and type raced to Dunkirk, braving mines, bombs, torpedoes and the ruthless airborne attacks of the German Luftwaffe. During the Dunkirk evacuation, the Royal Air Force (RAF) successfully resisted the Luftwaffe, saving the operation from failure. Still, the German fighters bombarded the beach, destroyed numerous vessels and pursued ships within a few miles of the English coast. The harbor at Dunkirk was bombed out of use, and smaller civilian vessels had to ferry the soldiers from the beaches to the warships waiting at sea. But for nine days, the evacuation continued—a miracle to the Allied commanders and the rank-and-file soldiers who had expected utter annihilation.