World War II: The U.S. Army Air Force firebombs Tokyo, and the resulting conflagration kills more than 100,000 people, mostly civilians.

World War II or the Second World War was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were tried for war crimes.

On the night of 9/10 March 1945, the United States Army Air Forces (USAAF) conducted a devastating firebombing raid on Tokyo, the Japanese capital city. This attack was code-named Operation Meetinghouse by the USAAF and is known as the Tokyo Great Air Raid in Japan. Bombs, dropped from 279 Boeing B-29 Superfortress heavy bombers, burned out much of eastern Tokyo. More than 90,000 and possibly over 100,000 Japanese people were killed, mostly civilians, and one million were left homeless, making it probably the most destructive single air attack in human history, including the atomic bombings of Hiroshima and Nagasaki. The Japanese air and civil defenses proved largely inadequate; 14 American aircraft and 96 airmen were lost.

March 10 is the 69th day of the year in the Gregorian calendar; 296 days remain until the end of the year.