Baluarte de San Diego is located along the walls of Intramuros (The Walled City) in Manila, Philippines. And it is one of the oldest stone structure in Intramuros.
The place was first called as Fort Nuestra Señora de Guia. And the plan was to build a three tiers of circular walls, with the outer tier 28 feet high, 12 feet thick at the bottom, and 4 feet thick at the top. The construction was stopped when the tower threatened to collapse as it got higher. It was completed sometime between 1586 to 1587.
In 1593, the upper portion of the tower was demolished to form a new stone bulwark. This was also the year when the place was named Baluarte de San Diego. The construction was again completed sometime between 1653 to 1663. It was then shaped like an ace of spades.
In 1762, the Baluarte was damaged by the british forces. It was restored and strengthened when spanish people returned, but it was again damaged and abandoned after the 1863 earthquake. The World War II destroyed whatever remained of the structure.
The place was forgotten until 1979 when the excavation was done by the Intramuros Administration and the National Museum. The place was again restored in 1992.
The area is now managed by the Intramuros Administration.