The fifth-storey observation deck at the now-defunct View Road Hospital in Admiralty - located on a gentle hilltop - provides a view of the Causeway to Malaysia as well as Singapore's northern coastline.

This led researchers to believe that the site was used by the Japanese in wartime Singapore as a vantage point to observe its ships, as well as to guard against a potential British invasion from the Causeway - the same way the Japanese themselves entered Singapore from Malaya in 1942.

From noon today, the public can sign up for a free tour to learn more about the history behind the now-vacant hospital, which served as a branch of Woodbridge Hospital (now Institute of Mental Health) from 1975 to 2001.

The site, which is usually closed to the public, is among the highlights of the annual Battle For Singapore programme, which seeks to deepen Singaporeans' understanding of the country's World War II history.

The programme, which started in 2014, is organised by the National Heritage Board (NHB) with partners such as the Singapore Land Authority, members of the Museum Roundtable collective, and heritage groups including All Things Bukit Brown and National University of Singapore History Society.

A total of 74 tours are offered at various sites, along with public talks on topics such as prisoner-of-war art, as well as storytelling sessions by wartime survivors at the Eurasian Heritage Gallery.

These activities will take place from Saturday to Feb 29, as NHB commemorates the 78th anniversary of the fall of Singapore to the Japanese on Feb 15, 1942.

One nugget about the former View Road Hospital stands out. Archival documents show that it was in the middle of construction in 1941, and completed in 1945.

This suggested that the Japanese took over the construction during the Occupation, said Ms Alexandra Tan, manager of international and museum relations at NHB, during a media preview last week.

The Japanese fear of being attacked from the Causeway was not unfounded, said Ms Tan, as the British did plan a series of operations where they would capture Port Swettenham (now Port Klang) along the western coast of Malaya before making their way down to Singapore.

"But, in actual fact, a lot of these operations weren't fully implemented because of other military confrontations around the region, in particular, the dropping of the atomic bombs in Japan, that made the British re-entry into Singapore less violent," she said.

UNDERSTANDING IMPACT OF HISTORY We hope to interest more Singaporeans in our WWII history so that they can understand the impact of the Japanese Occupation on Singapore and Singaporeans, better appreciate the WWII buildings and sites in Singapore, and reflect on the importance of remembrance, resilience, and reconciliation. MR ALVIN TAN, deputy chief executive for policy and community at the National Heritage Board, on the tours.

Another new guided tour offered is at the former Admiralty House in Old Nelson Road near Sembawang which used to house key military commanders and was gazetted as a national monument in 2002.

It features an underground bunker discovered in 1990 by a former general manager of Yishun Country Club who wanted to do some landscaping when an excavator sank into a cavity in the ground.

While there is limited information available on the bunker's use, it was likely constructed by the Japanese officers stationed there during the Occupation, according to NHB's research. One reason for this is the presence of a concrete squat toilet, which was less likely to have been used by British naval officers.

Deputy chief executive for policy and community at NHB Alvin Tan said that through past editions, they learnt that guided tours at publicly inaccessible and lesser-known sites were very popular.

"We hope to interest more Singaporeans in our WWII history so that they can understand the impact of the Japanese Occupation on Singapore and Singaporeans, better appreciate the WWII buildings and sites in Singapore, and reflect on the importance of remembrance, resilience, and reconciliation," he said.

Sign up for the tours at www.museums.com.sg. Slots are allocated on a first come, first served basis.