China: In the Henan province of China, there are underground dwellings in which there are about 10,000 homes and currently 3,000 people still live there.
They are called Yaodongs, and have had six generations living under their roofs for over 200 years.
These caves are designed in such a way that they are strengthened with natural materials on their pit walls with its length ranging from 33 to 39 feet and depth 20 to 23 feet.
According to the news article published in daily mail, however, these subterranean ‘pit yards’ date back to stone age, most probably 4000 years ago. They are listed as intangible form of cultural heritage by the Chinese authority in 2011 and are currently under conservation.
They became widely popular under Ming and Qing dynasties. Today many of these dwellings became modernized, equipped with electricity and the temperature in these dwellings in winter is over 10 degrees Celsius in winter and 20 degrees Celsius in summer.