The artificial harbor of Arromanches-les-Bains constitutes an engineering feat. This assemblage of floating roads and unloading platforms that rose and fell with the tides enabled the sending of supplies and reinforcements to Allied forces during World War II. To ensure a calm water area at the port, a roadstead was created by submerging hollow concrete blocks and old boats. After the liberation of Arromanches on the evening of June 6, 1944, the first Phoenix breakwaters, keys to the victory, were submerged.