Hekeng, located in Shuyang Town, Nanjing County, 58 kilometers away from the county seat, is a relatively closed ancient village. It also has 16 earth buildings with different styles, which overlook the whole village from the air and are distributed in the form of Big Dipper seven stars. Among them, the oldest one was built in 1549, which has undergone vicissitudes of nearly 500 years and is still in use. In River pits, earth buildings are divided into circular and square buildings, and circular earth buildings are the most difficult to build. Generally, it takes two or three years to complete an earthen building, and even decades and generations of artisans have to pay for it. Earlier earthen buildings were constructed of clay, bamboo, wood and stone in the mountains. Exterior walls were built first, and walls were built with clay. Usually the wall is thick below and narrow above. The wall diameter of large earth building is about 1.5 meters. After the wall is finished, the interior wall is built with wood.