We are walking around Fort Pulaski East of Savannah, Georgia on the North Branch of the Savannah River. Down deep in the vaults of the fort is the super thick brick arches that protected the canon and personal from incoming artillery shells. The dark arches on the floor were wrought iron metal to run the wheels of the larger guns on so they could be turned and aimed.
I love the picture of the historical building, but I will be terrified if I need to go by myself in night.