During World War II, Hart Island was used as a disciplinary camp for Navy, Coast Guard and Marine personnel. Three German prisoners of war captured from a U-boat that surfaced in the Long Island Sound were imprisoned on Hart Island. After the war, ten acres at the northern end of the island were taken over by the U.S. Army. The DOC simultaneously used the area for burials, and inmates petitioned for permission to build a peace monument at the island’s highest point. In 1948, they built a 30-foot reinforced concrete memorial with the word "peace" written on one side and a simple cross on the other. The monument is elevated on a stepped base decorated with planters. This area was previously the location of Civil War-era barracks that were repurposed as prison facilities by the City. These structures are long gone except for a Civil War era cistern exposed in 2012 as a result of Hurricane Sandy on a steep bank northeast of the Peace Monument.