On the morning of December 7, 1941 the U.S. naval base at Pearl Harbor Hawaii was attacked by the Imperial Japanese Navy. The surprise attack was carried out by 353 aircraft from 6 Japanese aircraft carriers. Japan had also sent 5 midget submarines to attack the harbor, all of which were sunk or lost. One of the subs had been spotted outside the harbor and sunk before the aircraft attack began. This sub sinking didn't create the alarm that it should have, and the base remained unprepared for the coming aircraft attack. Japan's naval fleet that carried out the Pearl Harbor attack consisted of many ships including battleships, but they were only used to guard the carriers.

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