D-Day was history's largest air and sea invasion, involving around 160,000 troops on that day itself and many more in the ensuing Battle of Normandy. Of those 73,000 were from the United States, while 83,000 were from Britain and Canada. Troops started landing overnight from the air, then were joined by a massive force by sea on the beaches code-named Omaha, Utah, Juno, Sword and Gold, carried by 7,000 boats.