Fort McRee

Fort McRee was a historic military fort constructed by the United States on the eastern tip of Perdido Key to defend Pensacola and its important natural harbor. In the defense of Pensacola Bay, Fort McRee was accompanied by Fort Pickens, located across Pensacola Pass on Santa Rosa Island, and Fort Barrancas, located across Pensacola Bay on the grounds of what is now Naval Air Station Pensacola. Fort Pickens was the largest of these. Very little remains of Fort McRee today.

Source: Wikipedia