For the 4 islands in Manila Bay that used to be the Manila Bay Defense Forts, Corregidor-Ft. Mills, Caballo-Ft. Hughes, Fraile-Ft. Drum, Carabao-Ft.Frank.
Zf975. The clean-up seems to be complete in this photo. Malinta Tunnel West entrance basically looked the same until the 1975 to 1977 restoration got underway.