On February 16, 1945, the first of 7,000 American troops arrived at Corregidor, ready to retake the important Pacific outpost. To prevent its complete destruction, Manila was declared an open city when World War II broke out. The Japanese began their invasion of the Philippines on December 8, 1941, ten hours after the Pearl Harbor attack. They destroyed every US aircraft on the ground, forcing the American naval fleet to withdraw. Corregidor itself came under siege on December 29, 1941. After a two-hour bombardment, the Japanese destroyed or damaged the hospital, barracks, fuel depot, and officers club. The attacks on Corregidor continued for months. On March 11, 1942, General Douglas MacArthur escaped Corregidor but boldly stated, “I will return,” promising to come back and save the men he left behind.