The invasion of Normandy was code-named overlord.  It was planned for June 1944 when the weather should be good. It was important that where the Allies landed was a secret.

The best part to cross the channel would be the narrowest part, across from Dover, and this was where the Germans had most of there troops. In fact, the Allies chose Normandy.  They had a spy who convinced the Germans that the landing would be somewhere else.  So when they were going to land there were not so many Germans about.

The Allies used about 7000 ships, of which 4000 carried solders and weapons for the beaches and the other 3000 were to bombard the Germans from the sea or to carry supplies such as food, water, ammunition and medicine.

The Allies also needed a harbour. Since the big ships needed a place to dock and could not sail up to the beach. Huge artificial harbours were made (mulberry) these were than towed across the channel to Normandy. An ingenious underwater oil pipe was called Pluto.  The English oil pumping station was disguised as an ice cream parlour so that it would not be bombed.