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.
Thus starts the description on the National Park Service site for Ft. Pulaski.
The fort as seen by Tom
As seen by Ludwig: