This photo taken on May 16, 2021, shows the Guyaju Caves (Ancient Cliff House) in Yanqing district, northwest Beijing. The Guyaju Caves are an ancient dwelling built on a steep cliff. Over 100 stone chambers are preserved within the ancient dwelling. [Photo by Chen Chao/China.org.cn]

This photo taken on May 16, 2021, shows the scenery around the Guyaju Caves (Ancient Cliff House) scenic area in Yanqing district, northwest Beijing. [Photo by Chen Chao/China.org.cn]

This photo taken on May 16, 2021, shows the scenery around the Guyaju Caves (Ancient Cliff House) scenic area in Yanqing district, northwest Beijing. [Photo by Chen Chao/China.org.cn]

This photo taken on May 16, 2021, shows the Guyaju Caves (Ancient Cliff House) in Yanqing district, northwest Beijing. The Guyaju Caves are an ancient dwelling built on a steep cliff. Over 100 stone chambers are preserved within the ancient dwelling. [Photo by Chen Chao/China.org.cn]

This photo taken on May 16, 2021, shows the Guyaju Caves (Ancient Cliff House) in Yanqing district, northwest Beijing. The Guyaju Caves are an ancient dwelling built on a steep cliff. Over 100 stone chambers are preserved within the ancient dwelling. [Photo by Chen Chao/China.org.cn]

This photo taken on May 16, 2021, shows the Guyaju Caves (Ancient Cliff House) in Yanqing district, northwest Beijing. The Guyaju Caves are an ancient dwelling built on a steep cliff. Over 100 stone chambers are preserved within the ancient dwelling. [Photo by Chen Chao/China.org.cn]

This photo taken on May 16, 2021, shows the Guyaju Caves (Ancient Cliff House) in Yanqing district, northwest Beijing. The Guyaju Caves are an ancient dwelling built on a steep cliff. Over 100 stone chambers are preserved within the ancient dwelling. [Photo by Chen Chao/China.org.cn]

This photo taken on May 16, 2021, shows the Guyaju Caves (Ancient Cliff House) in Yanqing district, northwest Beijing. The Guyaju Caves are an ancient dwelling built on a steep cliff. Over 100 stone chambers are preserved within the ancient dwelling. [Photo by Chen Chao/China.org.cn]

This photo taken on May 16, 2021, shows a single stone chamber in the Guyaju Caves in Yanqing district, northwest Beijing. [Photo by Chen Chao/China.org.cn]

A boy visits the Guyaju Caves (Ancient Cliff House) scenic area in Yanqing district, northwest Beijing. [Photo by Chen Chao/China.org.cn]