The Reducto de San Francisco Javier was built in 1773 under the supervision of Engineer Dionisio O’Kelly. Restored in 1983, this defended the curtain wall from the bay. It also doubled as a storage area for ammunition and food supplies.
The reducto now houses the chapel of Our Lady of Guadalupe. Enshrined in the reducto is a copy of the image imprinted on the tilma of the shepherd to whom the Blessed Virgin Mary appeared in Guadalupe, Mexico.