Allied victory in Europe required the destruction of Nazi Germany. Great Britain and the United States committed to an invasion through France, Operation Overlord, to cooperate with the Soviet Union in achieving that goal.
A massive Allied force of almost three million built up in the British Isles. Allied bombing and French Resistance attacks isolated the future battlefield, while elaborate security and deception plans focused German attention in the vicinity of Pas-de-Calais.
On the night of June 5-6, 1944 American and British paratroopers landed in Normandy to secure egress from the beachheads, disrupt German counterattacks, and guard the flanks of selected beaches. On the morning of June 6, U.S. Navy, U.S. Coast Guard and Royal Navy amphibious craft landed six Allied divisions, massively supported by air and naval bombardment, on beaches code-named Utah, Omaha, Gold, Juno and Sword.
Difficult seas and weather interfered with the landings, as did staunch German resistance. The situation turned particularly desperate on Omaha beach, where soldiers from the 1st and 29th Infantry Divisions clawed their way up bluffs dominating the shoreline in the face of withering fire. Naval fire support was often at point-blank range. By day’s end more than 100,000 Allied soldiers were ashore, and a foothold had been established.
After further fierce fighting the Allies linked up the several beaches and pushed inland. Here they faced difficult bocage country, small fields broken up by centuries-old hedgerows. These favored the defense. More open country existed around Caen, but here German armored units massed for counterattacks that heavily attrited both sides.
The American VII Corps pushed across the Cotentin Peninsula to isolate Cherbourg by June 18, and secured that city ten days later after savage fighting. The British continued their attacks on Caen, pushing beyond the city by July 20 and drawing in German mobile reserves. Meanwhile the Americans attacked ground on through the bocage to secure St. Lo on July 18. Here they reached ground suitable for mechanized warfare, and the massive build-up of units and supplies within the beachhead positioned them for a breakout offensive.