When the sea goes out in Arromanches-les-Bains, a small village on the coast of Normandy in northwestern France, the large concrete pontoons that lie half submerged in the salty waters expose themselves in their entirety. These concrete structures played a significant role in the history of Europe, facilitating the landing of thousands of Allied troops and their equipment on the beaches of Normandy during Operation Overlord.

Mulberry harbour ruins in Arromanches-les-Bains, Normandy, France. Photo: Shandarov Arkadii/Shutterstock.com