What significant event occurred on December 7, 1941?

On December 7, 1941, the Japanese attack on Pearl Harbor led to the United States formally entering World War II. This event marked a pivotal moment in history, as it galvanized the American public and government to respond militarily to Japanese aggression after years of isolationist policies. The attack resulted in significant losses for the U.S. Pacific Fleet, prompting a declaration of war against Japan by the United States the following day.

The entrance into World War II not only altered the course of the conflict but also shifted the U.S. role on the global stage, leading to increased military engagement, alliance-building, and eventual victory in both the European and Pacific theaters. This moment is often referred to as a "day of infamy," underlining its historical significance and the profound impact it had on the trajectory of both American and world history.