Exercise Tiger

Exercise Tiger, or Operation Tiger, was the code name for one in a series of large-scale rehearsals for the D-Day invasion of Normandy, which took place on Slapton Sands or Slapton Beach in Devon. Coordination and communication problems resulted in friendly fire deaths during the exercise, and an Allied convoy positioning itself for the landing was attacked by E-boats of the German Kriegsmarine, resulting in the deaths of 946 American servicemen. The incident was under the strictest secrecy at the time due to the impending invasion, and was only nominally reported afterward; as a result it has been called "forgotten".