On this day in 1941, Japan launched a surprise attack on the U.S. naval base at Pearl Harbor, causing immense devastation. The attack killed 2,402 people, sank four U.S. battleships, and destroyed 188 U.S. aircraft. In response, the U.S. declared war on Japan, marking the beginning of its involvement in World War II. The assault, deemed a war crime due to the lack of a declaration, prompted U.S. President Franklin D. Roosevelt to declare it “a date which will live in infamy.” The attack’s focus on battleships, outdated in modern warfare, ultimately proved a strategic error for Japan.