Where did the allied troops practice for d day in the spring

On Slapton Sands (a beach in southwestern England). The d-day rehearsal was called "Operation Tiger" their plan was to get landing boats into the English Channel, then have them simulate a water landing on the beaches of the Devon coast. The rehearsal was led by Dwight D. Eisenhower. Unfortunately during the actual rehearsal in the English channel a German warship picked up the landing craft on its radar and launched an attack. The attack cost 800 men their lives.

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