Q: What was the Doolittle Raid?

A: See:
http://www.history.navy.mil/photos/e...-42/dooltl.htm

An amazing story of military audacity: Using the Navy to launch heavy
Army bombers (B-25s) against Tokyo on April 18, 1942, the immediate
effect was the destruction of the city's tinderbox slums, with great
loss of civilian life, but it precipitated the battle of Midway, a
month and a half later, in which four Japanese carriers were lost,
permanently crippling the Japanese Navy.

Wasn't the B-25 a medium bomber?

I know there was a joke among B-24 pilots about B-17's being termed
"heavy" bombers.