The National Day Istana Open House will be held online this year, with visitors getting a tour of rarely-seen features such as an air-raid shelter located in a cellar.

Known as the Bunker, it was refuge for staff of the Government House (as the Istana was previously known) during World War II.

Another feature typically closed to the public is a 14.5m-deep well that sits on the side of the Istana's main building.

It was likely built in 1869 by Indians who were convicts here, and who were involved in the construction of the Government House.

The hour-long event will be hosted on President Halimah Yacob's Facebook and Instagram platforms on Aug 2 from 10am, one week before National Day.

Unlike the Hari Raya Aidilfitri virtual Istana Open House in May, which was limited to invited guests, the National Day event will, for the first time, be open to everyone.

The event is being hosted online amid the coronavirus pandemic, with the multimedia tour organised by The Straits Times.

The virtual Open House will also include segments hosted by the National Museum of Singapore and the Asian Civilisations Museum.

Visitors can interact with an artefact from the National Museum in a curated digital space called Zoom into History, while the Asian Civilisations Museum will present sneak previews of its virtual galleries and National Day programme.

The National Day Parade 2020 organising committee will also introduce the Our Heart for Singapore project - which shares Singaporeans' reflections, thanks, hopes and aspirations for the nation - during the virtual tour.

Close to 150 beneficiaries of the President's Challenge and The Straits Times School Pocket Money Fund will join Madam Halimah for the virtual visit via videoconferencing.