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The Bismarck's base before Operation Rheinübung was in German-occupied Poland, specifically at Gotenhafen (present-day Gdynia). From this base, the Bismarck, accompanied by the heavy cruiser Prinz Eugen, embarked on its ill-fated mission to disrupt Allied convoys in the Atlantic Ocean. The operation, which began in May 1941, resulted in the famous Battle of the Atlantic and the eventual sinking of the Bismarck by British naval forces.