7 December 1941

The attack on Pearl Harbor was a surprise attack on the United States naval base at Pearl Harbor on Oahu, Hawaii on the morning of Sunday, 7 December 1941, which brought the U.S. into World War II. Aircraft from the Imperial Japanese Navy destroyed five U.S. Navy battleships, along with 188 aircraft, one minelayer, and three destroyers and inflicting over 4,000 casualties. The Japanese losses were minimal at 29 aircraft and five midget submarines with 65 Japanese servicemen killed or wounded.

The intent of the pre-emptive strike was to protect Imperial Japan's advance into Malaya and the Dutch East Indies — for their natural resources such as oil and rubber — by neutralizing the U.S. Pacific Fleet (in the fashion of War Plan Orange as practiced by both sides).The Japanese high command was (mistakenly) certain any attack on the United Kingdom's colonies would inevitably thrust the U.S. into the war. By contrast, President Franklin D. Roosevelt had moved the fleet to Hawaii, and ordered a buildup in the Philippines, to deter Japanese aggression against China, or European colonies in Asia.
The attack was one of the most important engagements of World War II. Occurring before a formal declaration of war, it spurred the U.S. into World War Two against Japan and then Germany which declared war on the U.S. a few days later, creating a conflict that encircled the world. Roosevelt called December 7, 1941 "a date which will live in infamy".