The pivotal event that began on December 7, 1941, bringing the United States into World War II, was the attack on Pearl Harbor. This surprise military strike by the Japanese Navy against the U.S. naval base in Hawaii resulted in significant loss of life and damage to the Pacific Fleet. The attack galvanized public opinion in the U.S., leading to a declaration of war against Japan and, subsequently, against the Axis powers. Pearl Harbor marked a turning point in U.S. involvement and strategy in the global conflict.