The guy smoking:

Big Rain, 21, a KTV lounge worker, is seen in his basement room beneath Beijing’s north Third Ring Road, Beijing, China, May 9, 2011. Originally from Heilongjiang in China’s northeast, he’s been in Beijing for the past year. Faced with sky-high property prices, living underground is often the only option for this legion of low-waged migrant workers, who make up one-third of Beijing’s estimated 20 million people.

Millions of Chinese citizens come from across the country with dreams of making it big in the capital. Faced with sky-high property prices, living underground is often the only option for this legion of low-waged migrant workers, who make up one-third of Beijing’s estimated 20 million people. But they have been unkindly dubbed the “rat tribe” for making a home in Beijing’s 6,000 basements and air raid shelters—about one-third of the city’s underground space. They pay monthly rents of 300 to 700 yuan ($50 to $110) for partitioned rooms of seven to eight square meters, or sometimes, a closet-like space barely wider than a single bed.

Beijing-based photographer Sim Chi Yin‘s China’s Rat Tribe takes us inside and underground, capturing the small, dark spaces that millions have made their home. Originally presented at Photoville 2012 as part of a Magnum Foundation initiative to explore the meaning and value of home, the work is currently on view at United Photo Industries in Brooklyn through June 22, 2013.

The couple:

Twenty-four-year-old Jiang Ying and 23-year-old Li Ying sit in their basement room in central Beijing, China, May 14, 2011. Jiang Ying, a bar waitress, and Li Ying, an office worker, have lived here for one and a half years, making the room their own by adding bright pink wallpaper. Faced with sky-high property prices, living underground is often the only option for this legion of low-waged migrant workers, who make up one-third of Beijing’s estimated 20 million people.

The guy lifting weights:

Xie Jinghui, originally from Jiangxi, born in 1987, sometimes does some weightlifting in his basement room in Beijing, China, April 22, 2012. He used to live in a more central location within Beijing’s 3rd Ring Road, but one year ago the house was torn down. He says: “Everybody thinks that living in the basement is only a temporary thing but then people end up staying much longer… For my generation it’s difficult to stay at home but it is also difficult to live away from home in big cities.”