The Guyaju Caves, also known as the Yanqing Ancient Cliff House, is a rock-cut complex of honeycomb caves carved into the slopes of the Tianhuang Mountain in the Yanging District of China.
The site was first discovered in 1984 near the village of Dongmenying during a survey conducted by the Yanqing County Cultural Relics Management Office. Since then, Guyaju has been registered with the national key cultural relics protection unit, the highest protection level approved by the State Council of the People's Republic of China for immovable cultural relics.
Guyaju is situated in the northern margin of the Yanqing-Fanshan Basin, a geological region comprising of 110-million-year-old granite that formed when magma intruded upwards through large amounts of diabase rock.
The cave builders took advantage of exposed granite features to construct a complex network of 350 chambers cut into the rock face across a system of 117 caves. The chambers are mainly 1.8 metres in height and laid out in a rectangular or square plan that vary from single room dwellings to larger multi-room homesteads over multiple levels.