Earthen houses (Tulou) represent a unique architecture of Hakka, that can be found around Fujian, Jiangxi, and Guangdong provinces following the flow of the Hakka people from central China to the South. Most of Hakka people resided in mountains, so communal houses made of compacted earth were built to provide protection against bandits and wild animals.

The older examples of this type of construction consists of interior building, which by large peripheral with hundreds of rooms and occupants. With all the halls, storage, wells and bedroom inside the large building towerlike functions almost like a small fortified city. Earthen houses are made of earth, stone, bamboo and wood, all readily available materials. After the construction of the walls with rammed earth, branches, strips of bamboo and wood chips were in the wall as "bones" to reinforce. The result is a well-lit and well ventilated, windproof, quake proof building that is warm in winter and cool in summer.

More than twenty thousands of these houses still stand today, ten of which are over 600 years old. The oldest, "Fu Xing Lou" in Hu Le town, was about 1,200 years old and is considered a "living fossil" of the style of central China. The Tulou is located on the border of the Yongding and Nanjing County County is the perfect example of this type of construction, and it is here that most of earthen houses. Most of the nominated properties are located in this area.