The endlessly adaptable plane began as a twinkle in its designers eye in the late 1930s. The United States’ Army Air Corps was looking for a new bomber, one capable of carrying at least a 5,000 pound payload. The twin-engined result was designed for a crew of three (pilot, navigator, bombardier), but soon expanded into a wider-body version that included gunners for self-defense. With no time to waste, the USAAC ordered 140 of the models from the drawings alone.

On this day, August 19, in 1940 the first B-25 “Mitchell” bomber, the mainstay of U.S. ground bombing in the European theater in WW II, had its first experimental flight. The design required 8,500 original drawings and 195,000 engineering man-hours total, but the end result was a bomber that could be mounted with a variety of devices and weapons for either ground attacks, altitude bombing, or reconnaissance

The Mitchell bomber’s claim to fame came from a completely left-field use. Early in the war against Japan, the U.S. decided launch a daring air raid on Tokyo, the enemy’s capital. There were no air bases to launch from, and the carrier planes had too short of a range, so the military came up with a way to modify the B-25 for carrier-based takeoffs. The raid worked, and the B-25 became known as the first bomber to ever attack Tokyo