Pearl Harbor is a natural harbor located on the island of Oahu, Hawaii. It is known for its deep waters and strategic location in the Pacific Ocean. The harbor serves as a major naval base and is home to the U.S. Pacific Fleet. On December 7, 1941, Pearl Harbor was the site of a surprise military attack by the Imperial Japanese Navy, which led to the United States' entry into World War II. Today, it is a historic site, featuring memorials such as the USS Arizona Memorial, honoring those who lost their lives during the attack.