诺曼底入侵后的桑树港遗址，法国诺曼底Arromanches les Bains Remains of Mulberry Harbour from the D-Day invasion, Arromanches les Bains, Normandy, France (© Javier Gil/Alamy)

诺曼底入侵后的桑树港遗址，法国诺曼底Arromanches les Bains / Remains of Mulberry Harbour from the D-Day invasion, Arromanches les Bains, Normandy, France (© Javier Gil/Alamy)

Engineering an artificial harbor in Normandy

For the 75th anniversary of D-Day, the beginning of the end of WWII, we're focusing on the remains of the Mulberry Harbours—one of the most impressive military engineering feats of the war. Knowing that the ability to land huge numbers of men, vehicles, and supplies would be crucial to the Allies' success of the invasion of Normandy, Winston Churchill challenged his forces to come up with an artificial harbor that could be towed into place and operational within days of the initial landings.

Over 40,000 men were involved in the creation of two harbors that were installed at Omaha and Gold beaches beginning on June 9, 1944, and which were completed just six days later. The harbors included breakwaters comprised of sunken decommissioned ships, pre-built concrete caissons, 33 jetties, and over 10 miles of roadways. A violent storm on June 19th destroyed the harbor at Omaha beach, but Mulberry B, at Arromanches, survived and by the time it was abandoned six months later it had landed 2.5 million men, 500,000 vehicles, and 4 million tons of supplies into northern France.