3. Castle Williams was Both a Prison and Community Center

Castle Williams, on the west point of the island, stands as  circular defensive structure made of red sandstone. Constructed between 1807 and 1811, it was considered the prototype for modern fortifications. It served as a prison during the Civil War and again in 1903. But in 1966 when the Coast Guard wanted to demolish it, the castle was remodeled as a youth community center. Its prisons cells were converted into nurseries, meeting rooms for Scouts and clubs, a woodworking shop, art studios, a photography laboratory and a museum.