The Regent International apartment building in Hangzhou, China with 30,000 residents

Located in Qianjiang Century City, Hangzhou’s central business district, the S-shaped Regent International was originally designed as a luxury hotel, but was subsequently converted into a colossal apartment building, with the rooms turned into thousands of high-end residential apartments. The impressive building is 206 m tall and has 36 to 39 floors, depending on what you’re side of it you’re on, and as any self-contained community, features a variety of amenities and businesses, like a giant food court for its tens of thousands of inhabitants, as well as swimming pools, barber shops, nail salons, medium-sized supermarkets, and internet cafes. You can find anything you need in the building, so technically you don’t even need to go outside.