Pearl Harbor, Hawaii, is famous in U.S. history. It was attacked by the Japanese on December 7, 1941. That attack led the United States to enter World War II. At that time, Hawaii was not a state. Instead, it was a territory of the U.S. Oahu is one of many Hawaiian Islands. Honolulu, the state capital, is on the island of Oahu.
In May 1940, President Roosevelt was worried. Japan had been invading its neighboring countries. It seemed that Japan wanted to take over Asia just as Adolf Hitler wanted Germany to take over Europe. Both Hawaii and the Philippines were territories of the U.S., and the United States had military bases in both places. Many American citizens lived in both places. In response to the Japanese threat, President Roosevelt moved the main base of the U.S. Pacific fleet from California to Hawaii.
Pearl Harbor was a sheltered bay on the southern end of Oahu. It was named Pearl Harbor because of the many pearl oysters found in the waters there. The bay made an excellent naval harbor. Many U.S. battleships were anchored there. The line of ships was known as "Battleship Row."