Within the next few decades, will Singaporeans work and live in an underground city teeming with activity? That seems likely in land-strapped Singapore, according to experts.
And the government, too, is seriously considering adding the development of subterranean or underground space to its conventional methods of building high-rise residential buildings and reclaiming land on its coastal areas to overcome land constraints.
Such efforts could be seen in the underground space masterplan, which is expected to be released this year by the Ministry of National Development (MND). The high-level Economic Strategies Committee has also named underground space as a "strategic resource".
Existing subterranean projects like the Jurong Rock Caverns and the Underground Ammunition Facility (UAF) are quintessential examples of how Singapore overcomes its land constraints by tapping on underground space.
For instance, the Jurong Rock Caverns, which is deployed as an underground oil storage facility, frees up 60 hectares, or about 70 football fields of usable land above ground.
Meanwhile, the UAF at Mandai saves 300 hectares of aboveground space. On top of that, as the UAF is less prone to the effects of the weather, maintenance and energy, costs are less than 50 per cent of similar aboveground facilities.
Most of the island's current underground projects are for storage and transport purposes, and the government is also exploring the possibility of working and living below ground, too.
JTC Corporation, the national developer of industrial infrastructure, has embarked on a study of unprecedented scale beneath the Singapore Science Park in the western part of the country. The proposed underground Science City, which could house research laboratories, offices and data centres 30 storeys below ground, hopes to encompass the ever-growing demand for research talent in Singapore yet at the same time maximise land use.
David Tan, assistant CEO of JTC Corporation, highlights the importance to building underground, in addition to the current science complex above ground.
"By putting an underground science city between Science Parks 1 and 2, we could actually have two plots of land for development -- one at the bottom, underground; the other one on top. The key is really to see how we can use a piece of land twice," he said.
The study -- set to be completed by April this year -- is touted by JTC as "a costly yet much-needed experiment", as land becomes increasingly scarce.
However, as Singapore's subterranean expansion is still in its early stages, it is difficult to paint a clear picture of how an underground city will exactly look like.
According to the information found at the Singapore City Gallery, there are limitations to expanding sideways by reclaiming land. It cites rising sea levels caused by climate change might affect reclaimed land in the future.
Furthermore, there is a limit to land reclamation. "Ultimately, we can only reclaim land up to a point because we need our sea space for shipping and recreation. We also need to respect international boundaries. In addition, water beyond 20m deep becomes too costly to reclaim using current technology," the exhibits at the gallery wrote.
In Amsterdam, the Holland government is planing to build an underground city -- a US$14.4 billion (S$18.6 billion) project -- that aims to create a vast underground mixed-used complex beneath the city's canals and streets.
Construction work is expected to begin in 2018, and have a duration of approximately 10 years, according to online reports.