Mulberry B at Arromanches

There were two Mulberries constructed on the D-Day beaches, one at Arromanches on the British landing beach known as Gold Beach, and the other on the west end of Omaha beach. Most readers are probably wondering "what the hell is a Mulberry?". There's a lot of backstory, so prepare for the boring exposition part.
In 1942, a Canadian division made a raid on the French coast at the port of Dieppe. The idea was to capture the port, hold it briefly, then bring the troops back off, to get some experience and try things out. It was a fiasco. Nothing went right, and the bulk of the Canadian troops were killed, wounded, or captured. The Germans took one lesson from from the Allied failure at Dieppe, the Allies took a different lesson. The difference in their responses would prove to be telling.
The Germans decided it was important to invest more resources in the defense of ports. The Allies, on the other hand, decided that attacking ports from the sea was a very bad idea, and replanned the invasion so that they would be attacking beaches rather than ports.
The only problem with the Allied decision was that if they didn't take a port, well, then they didn't have a port. This is one of those cases where Churchill's enthusiasm for oddball ideas paid off. I'm not sure if it was really Churchill's idea or not, but he certainly was one of its biggest advocates, and he is often given credit for it. What was the idea? The British built two complete artificial ports out of floatable concrete and steel structures and sank them underwater to hide them. Once the troops were ashore in Normandy, the two artificial ports, Mulberries A & B, were raised from the bottom, towed across the channel and placed at Omaha and Gold beaches by June 9th, 1944.
The notorious channel storm of June 19th destroyed the Mulberry at Omaha Beach, and almost no traces are left of it today. Some parts from it were used repairing Mulberry B, which was in much better shape. Supposedly the British engineers on Gold Beach took much better care anchoring the Mulberry than the US engineers at Omaha. Mulberry B operated for 10 months after being built, and much of it remains at Arromanches, where there is also an excellent museum devoted to the Mulberries.
The photo shows pontoons that supported the steel roadways running out into the port area, sitting on the beach. Large breakwaters are visible off in the distance.