There’s a reason Hong Kong earned a reputation as a concrete jungle. Both people and skyscrapers pack its busy streets. One behemoth building in particular offers an astounding visual of its immense population. Its individual units are stacked one on top of the other and create a colorful, cohesive tapestry of homes.

Quarry Bay is a densely packed neighborhood in Eastern Hong Kong, with more and more industrial and residential spaces opening each year, but perhaps no building is quite as condensed as the “Monster Building.”

The Monster Building, as it’s been nicknamed by locals, isn’t actually a single building, but an E-shaped complex composed of five connecting structures: Oceanic Mansion, Fook Cheong Building, Montane Mansion, Yick Cheong Building, and Yick Fat Building. They were built during a population boom in the 1960s to offer government-subsidized housing for low-income residents.

The compound has a similar look to other subsidized housing built in the same decade, when the upper floors of the building were used as residences and the lower floors were used for shops selling tea, fish, and other groceries and household goods. Because of its photo-friendly symmetry and aesthetically striking architecture, the building has become a favorite spot for urban explorers and Instagrammers. The area has been used as a set in multiple films, including Ghost in the Shell and Transformers.

With the growth of popularity, photographing the building has become more challenging due to a ban on public access to the inner courtyard.