About 20 million Chinese still reside in caves and dirt-covered dwellings on the Loess Plateau that straddles of the Yellow River in China's northwest. Some of the caves have been passed down for generations, with hard-packed earthen walls, electrical wiring, plumbing and other modern conveniences, including cable television. Longtime cave dwellers are often passionate about their way of life, saying they are shielded from the elements in a practical and efficient fashion, dwelling along hillsides and leaving valuable arable land in valleys for growing crops.
An entire village of Maew (Miao) people in China is living in a cave which is about 700 feet deep. They have houses, a school where children study during day time. Their building don't have roofs because they don't need them.
The town of Coober Pedy in South Australia, where opals are mined some miners live in underground houses