Fort Pulaski National Monument is located between Savannah and Tybee Island, Georgia. It preserves Fort Pulaski, notable as the place where, during the American Civil War, in 1862, the Union Army successfully tested a rifled cannon. The success of the test rendered brick fortifications obsolete. The fort was also used as a prisoner-of-war camp. The National Monument includes most of Cockspur Island (containing the fort) and all of adjacent McQueens Island. - Wikipedia