On June 6, 1944, the allies embarked on the largest seaborne invasion in history. If the allies hasn't been successful, one can only imagine what the world would be like right now.
"The Normandy invasion began with overnight parachute and glider landings, massive air attacks, naval bombardments, and an early morning amphibious phase began on June 6. The “D-Day” forces deployed from bases along the south coast of England, the most important of these being Portsmouth. The battle for Normandy continued for more than two months, with campaigns to establish, expand, and eventually break out of the Allied beachheads, and concluded with the liberation of Paris and the fall of the Falaise pocket in late August 1944." (more)
The National D-Day Memorial Foundation