The Atlantic Wall was a series of coastal fortifications built by Nazi Germany during World War II. Stretching from Norway to the French-Spanish border, it was designed to defend against an anticipated Allied invasion. Construction began in 1942 and included bunkers, artillery positions, and obstacles to deter landing forces. The wall was most heavily fortified in northern France, particularly around the area of the Normandy landings. Despite its extensive defenses, the Allies successfully invaded on June 6, 1944, during D-Day, leading to the eventual liberation of Western Europe from German occupation.