Every 30 years, this Chinese mountain ‘lays eggs’: What lies behind the mystery?

China’s ‘Egg-Laying Mountain’ in Guizhou Continues to Astonish Scientists and Locals (Image: Social Media)

A quiet cliff in Guizhou Province, Chan Da Ya, or the "egg-laying mountain", has again drawn global curiosity as smooth stone "eggs" roll down its face every couple of decades in a mysterious fashion, leaving scientists and locals fascinated by this rare natural wonder.

Unlike an active volcano, the cliff produces no sound or visible warning. Yet, about once every 30 years, large oval stones emerge and tumble down the slope. Some weigh hundreds of kilograms, and their appearance has long puzzled geologists. According to a Times of India report, the cliff consists of soft limestone mixed with harder rock. Wind and rain erode the softer layers over time and expose the solid, egg-shaped stones inside. When erosion finally completes its slow work, the stones fall, giving the appearance that the mountain is "laying eggs".

These stone "eggs" are a treasured symbol among the Shui people from the neighbouring Gulu Zhai village. Many families keep them at home, believing they hold spiritual energy, for auspicious luck and protection. This kind of belief has been passed down through generations to show how much this civilisation connected with the natural world that surrounds them. To the Shui, the stones represent heritage and harmony with nature.

Geologists that study the cliff continue to research how these stones form and fall. They confirm that the process is a result of uneven erosion: the softer rock wears away faster than the harder material. But to this date, science cannot predict when the next "egg-laying" will occur. This remains one of the world's most patient and mesmerising geological displays, unfolding over decades.

Besides being a natural wonder, this cliff is famous for having ancient carvings and inscriptions, depicting stories of the region's history. These engravings give insight into the customs and beliefs of early inhabitants. Believed to bring good fortune, locals consider the site a protector of people, animals, and homes in the vicinity, making the place a spiritual as well as a cultural landmark. Today, Chan Da Ya attracts visitors, researchers, and believers alike. Tourists come to see the stone “eggs”, while scientists continue their study of this rare geological mystery. To the Shui people, it remains a sacred reminder that nature and tradition can coexist in harmony, shaping both science and culture in the heart of Guizhou.