placesandpalaces:

A Hakka walled village is a large multi-family communal living structure that is designed to be easily defensible. This building style is unique to the Hakka people found in southern China. 

 The Hakkas who settled in mountainous south western Fujian province in China developed unique architectural buildings called tu lou, literally meaning earthen structures. The Hakkas set up these unique homes to prevent attack from bandits and marauders. The tu lou 土楼; are either round or square, and were designed as a large fortress and apartment building in one. Structures typically had only one entranceway and no windows at ground level. Each floor served a different function – the first hosts a well and livestock, the second is for food storage and the third and higher floors contain living spaces. Tu lou can be found mostly in south western Fujian and southern Jiangxi provinces. Tulou buildings have been inscribed in 2008 by UNESCO as a World Heritage Site.