SINGAPORE - Hidden behind lock and key lies a 1942 British bunker where explosives were stored. Back then, carts on a railway track would send ammunition into the underground bomb-proof facility.

About the size of two five-room flats, the well-preserved structure will open to the public for the first time in more than seven decades next month. The National Heritage Board (NHB) announced today that it will be conducting eight English and two Chinese tours of the Armament Depot.

It is part of their efforts to commemorate Singapore's fall to the Japanese 73 years ago and its subsequent liberation three years later.

The bunker is the last of six others that used to dot Talbot's Hill in Woodlands. It is nestled in a dense forest that comes with a clear coastal view of Johor Bahru in Malaysia. The ammunition supported the British Naval Base's operations nearby. The historic site was later used by the Japanese to store their own ammunition which included anti-aircraft weapons and rifles.

Reaching the bunker requires a trek through muddy water and careful navigation across thick vegetation and creeping vines.

The bunker lies behind two large steel doors and a pool of water where small fishes dwell, has to be crossed first before one can get to the the dim facility.

The site was handed over to the Ministry of Defence in 1971. The ministry called it the Sembawang Ammunition Depot and gave it a fresh coat of paint. It was decommissioned in 2002 and both the bunker and the land were returned to the state.

NHB's group director of policy Alvin Tan said: "We hope that Singaporeans will get to learn more about World War II history and remember the wartime bravery, resilience and sacrifices of soldiers, Prisoners of War and civilians through these activities."

Each NHB tour can take about 25 people and members of the public can start booking slots on Thursday. More information will be released on the board's website and Facebook page. Some of the artefacts will go on display in a separate exhibition later this month.

melodyz@sph.com.sg