HDB flats are unique to Singapore.
More than 80 per cent of the population live in one, touted as public housing for the masses.
The design and construction of such buildings are such common occurrences, people often don't take a second look.
But HDB flats have come a long way since they were first mooted as a solution to a young nation's problem of clothing and feeding its people.
According to HDB, the so-called "public housing" was first set up in the 1960s, following a housing crisis in the nation.
While many of the older estates have since been upgraded or redeveloped, or even torn down, one Facebook group has taken to showcasing the HDB estates of old as a glimpse into how things started and how far we have come.
HDB estates of the past
HDB estates of the past appear in vintage or black-and-white photos, showing older HDB housing estates' starting point, many of which are still around today, but surrounded by newer buildings and amenities.
In the east, there are photos of the new flats built by HDB following the first land reclamation project of the Kallang Basin.
The area also features some of the first few point blocks and executive flats built in the Bedok and Chai Chee area in the 1970s and 1980s.
Towards the south, there are snapshots of Singapore's first satellite town in Queenstown.
In Queenstown, Blocks 45, 48 & 49 Stirling Road were allegedly one of the first few blocks of flats completed in October 1960, months after HDB's conception earlier that year.
In the West, Clementi New Town was the eighth new town to be developed by HDB, with the development primarily taking place between 1975 and 1979.
More than 800 villagers were resettled to make way for the new town, according to resources from the National Library of Singapore (NLB).
Woodlands, which has been Singapore's main mode of transport to Johor, Malaysia, since 1923, also primarily consisted of villages and squatters, before it was developed in 1972.
Spaces were subsequently planned to cater to the needs of the population, including transport networks, town centres and recreational facilities.
Nostalgia is real with this one.
Top image via HDB estates of the past Facebook