December 7, 1941 – the day that will live in infamy. The attack on Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service against the United States naval base at Pearl Harbor, Hawaii. The attack, also known as the Battle of Pearl Harbor, led to the United States' entry into World War II. The Japanese military leadership referred to the attack as the Hawaii Operation and Operation AI, and as Operation Z during its planning. At 7:48 am, Japan began their attack on the United States, and over the next seven hours continued with the U.S. held Philippines, Guam and Wake Island. Much of the U.S Pacific Fleet was destroyed in the attack, and over 2,000 sailors were killed. And thus, the Pacific War began.