Fort Drum, known as "concrete battleship" - heavily fortified island fortress located at the entrance to Manila Bay right in front of the island Korredigor.

After the Americans received from the Spanish control of the Philippines, Fort Drum was planned as a control station for mine warehouses. However, due to the imperfect system of defense in the area, the plan was revised: it was decided to align the island, and then build on it concrete structure, equipped with two 12-inch guns. Later, the War Department decided to replace the 12-inch guns on the 14-inch, and set the casemates with two 6-inch guns. In addition, it was planned to enclose a fortress concrete walls with a thickness of 7, 6 to 11 meters.

Construction began in April 1909 and lasted five years, during which the island Frehley was almost razed to the sea level, and on its surface were placed thick layers of steel-reinforced concrete, which then turned into a massive structure resembling a ship. By 1916, 14 have been installed - and 6-inch guns. There were also mounted searchlights, anti-aircraft batteries and fire control unit. Inside housed living quarters for 320 officers and men, generators, command posts and ammunition storage.

Right before the outbreak of hostilities in the Pacific in December 1941, Fort Drum was manned by soldiers. January 2, 1942, they reflected the airstrike Japanese bombers. In mid-January, it installed a new 3-inch gun. During February, March and April the fort survived several artillery shelling and air raids, sank several landing barges, intending to attack the island Korredigor and other fortified island. However, in May 1942, Fort Drum was delivered to the Japanese, and behind him and the island Korredigor.

Only in 1945, the fort was stormed by the Americans as part of the operation to liberate Manila. After heavy fighting in the air and at sea, American soldiers had access to the roof of the fort and were able to lock up the Japanese garrison inside. Once it was decided not to attempt to break into the fort, and to use the method, already tested earlier on Caballo Island in Fort Hyudzhs. There the soldiers pumped a mixture of oil and gasoline in the trenches and mortar, at a distance, it was set on fire with tracer bullets. In such a mixture of Fort Drum was flooded in through the vents on the roof, but instead of bullets to use the remote handset. Locked inside the Japanese soldiers were killed, and fire lasted for several days.

After all the forts in the territory of Manila Bay were reclaimed from the US-Philippine troops, the Japanese began to retreat. The ruins of Fort Drum with his incompetent Armoury Tower and the 14-inch guns, and today can be seen on the surface of the waters of Manila Bay.