Tianluokeng

West Fujian’s Hakka people, a subgroup of the Han, migrated to South China during the Qin Dynasty and, to protect themselves from hostile locals, ingeniously constructed clusters of circular, fortress-like homes directly out of the elements. The Tulou rammed-earth structures of Nanjing County span 4 stories and up to 40,000 square meters, housing up to one hundred residents apiece – the epitome of Chinese communal living.

As seen in Tom Carter’s CHINA: Portrait of a People, the most comprehensive book of photography on modern China ever published by a single author. Available now from Blacksmith Books.
http://www.tomcarter.org
http://www.blacksmithbooks.com/9789889979942.htm
http://www.youtube.com/watch?v=pj1tqIg1SBU