Do Military Exercises Always Go as Planned?

War is hell, but even preparing for war can be pretty disastrous. One unfortunate example took place in 1944, as the American military was getting ready for the invasion of Normandy in hopes of ending World War II. Because the operation was so massive, U.S. commanders decided to run a rehearsal known as Exercise Tiger, prepping eight tank landing ships in an area of the English Channel known as Lyme Bay, off the coast of Devon and Dorset.

The ships carried hundreds of servicemen and equipment. Although live ammo was being used to make the exercise feel real, it was all supposed to be carried out quietly and in secret. But there was so much chatter on the radio that a group of German attack crafts became suspicious and discovered the operation. Without the presence of a destroyer to protect them -- one had been assigned the task but was pulled back for repairs -- the U.S. ships were easy targets for torpedoes.

The ensuing massacre cost the lives of nearly 800 Americans (or closer to 1,000 according to some reports), who were either killed in the fighting or died in the freezing water. Despite the catastrophe, news of the operation's failure was kept in check by U.S. leaders. The facts finally came to light decades later.

Some surprising facts about D-Day: