Fort Siloso Fort Siloso ( Chinese : 西乐索炮台 ) is the sole restored coastal gun battery from the twelve such batteries which made up " Fortress Singapore " at the start of World War II . The Fort is situated on the resort island of Sentosa ; it is restored as a military museum , and open to the public . History . Construction . The word Siloso is derived from a Malayan word meaning rock ( Sanskrit root : Sila ) . There was a huge rock at the mouth of Singapore ' s harbour which was very dangerous to shipping . With trade flourishing in Singapore due to the Suez Canal in 1869 , it was necessary to protect Singapore ' s port . Based on the report by Major Edward Lake of the Madras Engineers , a fort was built at Blakang Mati ( Sentosa ) in 1874 . As part of the fortification , Mount Siloso ' s top was blown off to flatten it for the installation of a gun platform . By the 1880s , gun batteries were located on Mount Siloso and Mount Serapong on Sentosa . Armament . By the 1880s , Fort Siloso had 7 - inch RML guns and two 64 - pounders . In the 1890s , five 10 - inch guns were installed . These guns were operated electrically from an underground power - house . In the 1930s , twin 6 - pounder , quick - firing anti - torpedo boat guns ; five searchlights ; an Operational Tower ; two machine - guns and two twin Lewis anti - aircraft machine guns were added due to reports of impending war . The Fort was manned by the British Royal Artillery and the Singapore Artillery Corps . World War II . The forts were built to defend the land against sea invasion from the south . However , during World War II , the Fort ' s guns were turned 180 degrees inland to defend against land invasion by the Japanese Army in the west . The Fort ' s guns were fired at Japanese positions and troops who were advancing toward the city from Tengah Airfield . < br > British and local troops , were retreating from the overrun Pasir Laba Battery and heading back to British lines via the sea , when they were fired upon as they were mistaken for the enemy . This building is now known as the Surrender Chambers and has a vivid portrayal of the scenes of British and Japanese surrender with actual footage of the war being played interactively . This is on the upper storey , the ground floor has been turned into a souvenir shop . During the Japanese Occupation , the Fort was used as a prisoner - of - war camp . Post World War II . After the Japanese surrender , the Royal Navy occupied the Fort in 1946 , its guns were manned by the 1st Malay Coast Battery and the Royal Artillery . Gurkha detachments took over manning the guns when the British gunners were withdrawn and the 1st Malay Coast Battery was disbanded . Fort Siloso was manned by the 10th Gurkha Rifles to prevent Indonesian saboteurs from landing on Sentosa and Keppel Harbour during the Indonesia – Malaysia confrontation between 1963 and 1965 , when Singapore was part of Malaysia . Fort Siloso became a Catholic Retreat for British forces until Sentosa was handed over to the Singapore Government with the British withdrawal in 1967 . Fort Siloso then came under the command of the Singapore Armed Forces . Fort Siloso was converted into a military museum in 1974 , displaying its history and guns . Other coastal guns from different parts of Singapore were brought here for display . It had previously held the display of the British Surrender .