For America, World War II began on December 7, 1941, with the attack on Pearl Harbor as part of Japan's day-long assault across the Pacific, while major American installations on Luzon in the Philippines were also devastated, beginning America's first great battle of the war. Two weeks later, Japanese forces began their amphibious invasion of Luzon, and by January 1942 American and Filipino Armies had been pushed south toward the Bataan Peninsula. Despite starvation, tropical disease, and dwindling ammunition and equipment, they continued fighting for three more months with support from courageous Filipino civilians. Their defense delayed the Japanese timetable for conquest of the Pacific by many months and allowed America to rearm for war. On April 9, 1942, American soldiers defending the Philippines were ordered to surrender, after which the Japanese assembled the prisoners of war and forced them onto the seven-day, 65 mile Bataan Death March. About 70,000 men began the march, and disease, hunger, thirst, and abuse by Japanese soldiers made each mile more deadly; more than 1,000 Americans and possibly 15,000 Filipinos died before reaching Camp O'Donnell.