Japan attacked Pearl Harbor on December 7, 1941, a surprise military strike aimed at the United States naval base in Hawaii. The attack led to significant destruction of the U.S. Pacific Fleet, resulting in the sinking of battleships and the loss of thousands of lives. Following this attack, the United States declared war on Japan, officially entering World War II. This event marked a turning point in the war and mobilized American society for total war, uniting different sectors of the population in the war effort and reshaping international political dynamics.