D‑Day is a military term designating a particular deadline for a military operation or invasion, and specifically its use as a byname for Operation Overlord, the invasion of Normandy, France on June 6, 1944, when Allied forces began their invasion of continental Europe in order to free it from German occupation during World War II.
History Professor Stephen Ambrose wrote:
|“||D-Day represents the greatest achievement of the american people and system in the 20th century. It was the pivot point of the 20th century. It was the day on which the decision was made as to who was going to rule in this world in the second half of the 20th century. Is it going to be Nazism, is it going to be communism, or are the democracies going to prevail?||”|