This week, the world is marking the 75th anniversary of D-Day, the beginning of the end of World War II. On June 6, 1944, 150,000 British, American and Canadian troops stormed the beaches of Normandy. It was a dramatic bid to free France from the Nazis with the biggest combined land, air and naval operation in history. We take a closer look at the strategy and intricate preparation it took to prepare the Normandy invasion but also the effect it had on the thousands who took part.