On Sunday morning, 7 December 1941, a Japanese war fleet arrived at the American naval base at Pearl Harbor, on Hawaii. The Japanese bombarded the Americans with bombs and torpedoes. When the attack was over, more than 3,500 American were left dead or wounded. Eighteen warships had been sunk and hundreds of aircraft had been destroyed or damaged.
Japan attacked the United States to prevent the Americans from thwarting Japanese plans for expansion in Asia. The surprise attack was carried out to perfection, but Japan did not defeat the US. The damage caused was soon repaired and the main American aircraft carriers were in other ports at the time of the attack. The United States were able to retaliate quickly.
On that same day, Japan also attacked Singapore, Malaysia, Hong Kong, Thailand, as well as American bases in the Philippines and Guam. As a result, Japan was now at war with Great Britain and Canada. Australia, New Zealand and the Netherlands also declared war on Japan, and the war spread rapidly across the East-Asia.
The American population regarded the attack as a cowardly act and stood behind its government's decision to declare war on Japan. In response, Hitler declared war on America on 11 December 1941, for Germany was an ally of Japan. This meant that Hitler had gained another strong opponent. From then on, the United States fought with the Allies against Nazi Germany.