On 6 June 1944 – 'D-Day' – Allied forces launched the largest amphibious invasion in the history of warfare. Codenamed Operation 'Overlord', the Allied landings on the beaches of Normandy marked the start of a long and costly campaign to liberate north-west Europe from Nazi occupation. D-Day forced the Germans to fight a two front war again just as they had in WWI. Yet again the Germans could not handle war on both sides of them. “By the end of June 1944, about a million Allied troops had reached France.” - "World War II." World Encyclopedia 2004. Reinforcements for the infantry of D-Day had come in. In other words, the D in D-Day merely stands for Day. This coded designation was used for the day of any important invasion or military operation. ... Brigadier General Schultz reminds us that the invasion of Normandy on June 6, 1944 was not the only D-Day of World War II.