60th anniversary of the Battle of Exercise Tiger
To my embarrassment, I didn't know about this at all until I heard about it on the radio five minutes ago.
In a practice session for the Normandy Landing, a landing force off Britain was attacked by German torpedo boats.
Casualties from this single battle, during a war exercise: 749 dead.
Yet the exercise was repeated anyway, and the Normandy invasion went off as scheduled. Another story on this can be found here.
