Through the end of the Second World War, New Jersey's coast and the entrances to the ports of Elizabeth, Newark , and New York City were defended by seacoast fortifications at sites such as Fort Hancock and Highlands in New Jersey and Fort Tilden in New York. By late 1945, however, the ability of a long-range aircraft to deliver an atomic bomb across oceans and continents had already been twice demonstrated with devastating results. Accordingly, as postwar tensions between the United Stats and the Soviet Union increased, the need to deploy anti-bomber defenses capable of defending American cities against a growing Russian bomber threat became increasingly acute.