Fort San Felipe sits on a promontory above Cavite City's old port district, and its thick stone walls still enclose a working naval installation — the headquarters of the Philippine Navy. The fort dates to the late 16th century and was the primary Spanish naval base in Asia for much of the colonial period. Ships were built and repaired here; treasure galleons loaded here for the run to Acapulco.
The fort is partially open to visitors; the Museo ng Cavite within the walls houses exhibits on the province's military and revolutionary history. The old walls, moats, and bastions are in reasonable condition and worth walking for the views over Manila Bay. Access is by tricycle from Cavite City proper.
The surrounding Cavite City peninsula, known as the "Old Cavite" area, retains several colonial-era streets and churches worth exploring on foot. The Cavite Cathedral and the ruins of older structures nearby give a sense of what the port town looked like in its Spanish prime.