At least that's the case in Chongqing, China, where an apartment building has been built with a train running through it.

Not only does the light rail passenger train pass through the 19-story residential building, it also has a transit stop there,. So apartment residents can just go to the sixth through eighth floors to hitch a ride.

Chongqing, located in southeast China, is a sprawling metropolis packed with 49 million residents, so architects and city planners have gotten really creative in making transportation and residential projects coexist in China's so-called "Mountain City."