Operation Bolero
Operation Bolero was the commonly used reference for the code name of the United States military troop buildup in the United Kingdom during World War II in preparation for the initial cross-channel invasion plan known as Operation Roundup, to be implemented in mid-1943. Also for its lesser contingency alternative, Operation Sledgehammer, to be executed in the fall of 1942 in the event of German setbacks or to ease Axis pressure on the Eastern Front.