On a dramatic bluff overlooking Pensacola Bay, 19th-century Fort Barrancas was built by slaves atop an abandoned 18th-century Spanish fort. The fort, now part of the National Park Service, has endless dark passageways to explore but not much in the way of displays. A half-mile away via a walking trail lie the ruins of Advanced Redoubt, a Civil War–era fort. Tours operate on Saturday only, at 2pm for Barrancas and 11am at Advanced Redoubt.