Georgia - Fort Pulaski National Monument

"A Turning Point in Military History - In the days before the Civil War, brick forts were America's main defense against overseas enemies. In one two-day battle during the Civil War, new technology proved its superiority to brick forts. The Union army used rifled cannons to compel a surrender by Confederates inside Fort Pulaski. No one ever built a brick fort again after the battle." Source: US National Park Service

Fort Pulaski, Savannah, Georgia was completed in 1847. Thanks to Christina of USA.