Steeped in history, the former Supreme Court and City Hall along the Padang are two of Singapore's most iconic buildings.
Come November next year, the National Gallery Singapore, which will house 19th- and 20th-century Singapore and South-east Asian art, will stand in their place.
Its predecessors' rich heritage is precisely why those undertaking the museum's design and construction are taking a subtle and delicate approach.
That responsibility falls on studioMilou Architecture, a Paris-based firm which specialises in museum design and the adaptive reuse of historical and heritage buildings, and its Singapore partner, CPG Consultants.
The contract was awarded to them in 2008. Construction of the museum began in 2011 and is now approaching its final stages.
StudioMilou has set up an office in Singapore and a team of 20 architects, exhibition designers and project coordinators, half of whom are Singaporean, have been involved in the project over the past five years.
The challenge of turning two distinct municipal buildings with offices that have low ceilings into a unified art museum of international calibre is made all the more daunting by the fact that both the Supreme Court and City Hall were gazetted as national monuments in 1992.
At about 60,000 sq m, the National Gallery Singapore will be comparable in size with some of Europe's foremost museums, such as the Museo Nacional Del Prado in Madrid and the Musee d'Orsay in Paris.
The Supreme Court building, built between 1937 and 1939, was the seat of Singapore's highest court from 1939 to 2005. City Hall, built from 1926 to 1927, was where the British accepted Japanese surrender in 1945, where then Prime Minister Lee Kuan Yew proclaimed Singapore's self-government in 1959 and where Singapore's first government was sworn in in 1965.
The project's principal architect Jean-Francois Milou, 60, notes that one of the biggest challenges faced by the team was finding a way to unify the buildings while respecting their historical identity.
"It is an exercise in modesty. You have to temper yourself and always be humbled by the existing building. To integrate it with delicacy is very difficult work. It must be subtle. A lot of time has been spent on subtle work, such as the lighting in the galleries, that no one will notice," he says.
This required an obsession with details - from materials, lighting, finishings to every architectural element. But that does not mean that things such as the comfort of visitors and air circulation have been compromised. They are, in fact, top priorities.
Mr Milou says: "The design shows our one major aim - to offer the community of Singapore the existing buildings in such a way that they can recognise the monuments and walk through their original structures, but for new and more creative purposes."
The attention to detail is precisely why studioMilou was awarded the $530- million project.
Ms Chong Siak Ching, 56, chief executive of the National Gallery Singapore, says she is happy with the design and progress. "It is satisfying to see how the buildings are being transformed and to witness plans on paper taking shape in stone, concrete, steel and glass, and with great attention to detail."
Much of the project's complexity also has to do with how the monuments have shifted over time. For instance, in the former City Hall, no two windows on the same level are the same. In the 80 years since they were installed, each window frame has uniquely shifted, tilted and patinated, so individual attention has been required in its restoration.
Meanwhile, modern building codes and utilities required for a world-class gallery, such as high-tech lighting, sprinklers, air-conditioning, dehumidifiers and even loading capacity and anti- terrorism regulations, meant that the buildings had to be modernised without compromising their historical integrity.
The walls along the building's facade, for example, had to be expanded to accommodate the new utilities, yet the facade itself could not be changed.
But these construction quirks have only inspired unique solutions from the design team.
For instance, to maintain the facade of the buildings and still allow natural light into the galleries, the walls on either side of the more than 200 windows in the museum have been extended inwards, creating individual alcoves in front of each window.
These spaces, which vary from 2m to 3.5m in length and 0.5 to 1m in depth, resemble bay windows with seating areas for visitors to rest or admire the artwork.
While the many requirements have slowed the design and building process, Mr Milou says the effort will be rewarding. "Singapore is making a statement about the importance of heritage by taking an existing building to make its national gallery, unlike cities such as Hong Kong and Dubai which are building galleries from scratch," he points out.
"It might take half the time to build those galleries, but here, we are working with something much more contained, and in Singapore, a place which is known for building, not necessarily for conservation, it might actually be more ambitious.
"It is one of the most complex constructions in Singapore ever."