Built in several stages, this bastion rises on the southwest front of the fortress. Its cannons exchanged fire with those of the Concepción Bastion in the walled city of Veracruz, protecting the navigation channel and port access. Inside, it features vaulted spaces that once served as storerooms and barracks for the Ulúa garrison. A circular tower was later added atop the parapet, where a lighthouse—manufactured in London and composed of a system of lamps and lenses—was installed. It operated with a clockwork mechanism and emitted an intermittent light to guide ships.