A ship made of concrete! World War II led to shortages in steel supply. In 1942, the U.S. government contracted McCloskey & Company of Philadelphia, Pennsylvania to construct a new fleet of 24 cement cargo ships. Construction of the fleet started in July, 1943 in Tampa, Florida. After the war, several of the ships were turned into a floating breakwater in Canada and ten more were sunk as a breakwater in Virginia. Although the end of WWII marked the end of large-scale concrete ship building, to this day, smaller recreational boats are still being made from concrete.