Fort Drum is one of the most unusual military fortifications in the world. In the early 1900s, the United States Army reshaped El Fraile Island at the entrance to Manila Bay into what amounted to a concrete battleship — the entire island was covered in reinforced concrete up to nine metres thick, with two twin-gun turrets mounted on top. It was virtually unsinkable and nearly impervious to conventional attack.
The fort sits in the waters between Corregidor and the Cavite coast, accessible by boat. The superstructure remains — rusted, fire-blackened, overgrown in places, and surrounded by open water on all sides. Access is not straightforward; the fort is technically restricted, and visits require coordination with local boat operators who know the area. The effort is rewarded with one of the strangest ruins in the Philippines.
The story of the fort's final days in 1945 is as dramatic as its design: after failing to take it by conventional assault, American forces lowered hoses into the fort's air vents and filled the interior with burning oil. Daytrips to the area can be arranged from Cavite City combining Fort Drum with Corregidor for a full day on Manila Bay.