Using the latest sonar technology, a unique expedition to map sunken Allied vessels off the Normandy Coast reveals stunning images from beneath the waves. There are over a hundred shipwrecks in the English Channel of the landing craft and ships that took part in the greatest amphibious Invasion Fleet ever assembled. As the water drains away, we reveal extraordinary, secret technology deployed by both the Allies and the Nazis in the battle for western Europe. The outcome of that conflict changes our world forever.