What happened at Fort Sumter?
to build up a sand bar in the entrance to Charleston harbor, which the site dominates; The fort was a five-sided brick structure, 170 to 190 feet long, with walls five feet thick, standing 50 feet over the low tide mark. It was designed to house 650 men and 135 guns in three tiers of gun emplacements, although it was never filled near its full capacities.