Yongding (永定 县) is a county of the prefecture-level city of Longyan in Fujian Province on the border with the province of Guangdong.
The circle is known by the Hakka fortress houses. It involves circular buildings of two or more concentric circles. The walls consist of a mixture of soil, lime, cooked sticky rice and brown sugar with wood strips and bamboo as a frame. They were built to withstand strong winds, earthquakes and enemies.
The mountain village with its special house construction is unique in the world. The complex in Yongding is distinguished by its long history and huge proportions. It consists of numerous round and square buildings, each with about 360 to 400 rooms.
Initially, only two round towers ( Yuanlou ) were built. Later, the square towers ( fanglou ) were added. They were built of rammed earth and had up to five stories. Women surveyed, the building of a concentric ring of lower buildings and a courtyard.