The Mulberry Harbour in Arromanches, France, played a pivotal role in the success of the Allied invasion of Normandy during World War II. Constructed as part of the D-Day landings in June 1944, it was one of two temporary harbors designed to facilitate the rapid offloading of troops, vehicles, and supplies necessary for the liberation of Western Europe. Arromanches was chosen as the location for Mulberry B, nicknamed "Port Winston" after British Prime Minister Winston Churchill.

The harbor was an engineering marvel, consisting of pre-fabricated concrete caissons (known as Phoenix Caissons), floating roadways, and steel piers. These components were towed across the English Channel and assembled off the coast of Arromanches within days of the invasion. The structure created a sheltered area where ships could dock and unload cargo, even in rough seas.

Mulberry B proved remarkably durable. Over the following months, it handled an astonishing volume of supplies, playing a critical role in sustaining the Allied advance.