Visitors can view thousand-year-old stone inscriptions through glass windows at a depth of 40 meters underwater in the Yangtze River at the Chongqing Baiheliang Underwater Museum.

An inscription bearing the name Baiheliang, or White Crane Ridge, at the underwater museum.

A bird's-eye view of the museum.

Crowds of visitors during this year's Mid-Autumn Festival in late September.

A tourist poses for a photo while visiting the museum.

At the recent 2026 Yangtze River Civilization Forum held in Chongqing, a millennium-old Chinese stone ridge known as Baiheliang, or the White Crane Ridge, took center stage in discussions about its historical and cultural significance.

Located at the confluence of the Yangtze and Wujiang rivers in Fuling district, Southwest China's Chongqing, this remarkable hydrological site featured prominently in a promotional video screened during the forum's opening ceremony in mid-September.

The event also highlighted an ongoing cooperation between China and Egypt to seek World Heritage status involving Baiheliang in Chongqing and the Raoudha Nilometer in Cairo. It underscored the historical ties and shared scientific achievements of the two ancient civilizations.

Baiheliang is renowned as an ancient natural hydrological observation station. The ridge stretches about 1,600 meters in length and 15 meters in width. Named after the white cranes that once gathered there, it bears records of water levels and 72 drought years spanning the period from 764 to 1963.

Known as both the "Ancient Hydrographic Station" and the "Underwater Stele Forest", the site contains more than 165 inscriptions, carvings of 18 stone fish, two Guanyin (Bodhisattva), and a white crane. These features demonstrate the scientific knowledge, historical record-keeping and artistic skills of ancient China, local authorities said.

Baiheliang's transformation into an underwater museum was prompted by the Three Gorges Project, which submerged the ridge beneath about 40 meters of water, requiring innovative measures to preserve the site.

The museum adopts an in-situ preservation strategy based on a proposal put forward by academician Ge Xiurun in 2001.

The plan involved enclosing the site within an elliptical metal structure through which filtered and purified river water circulates, preventing sediment from accumulating and reducing erosion while maintaining balanced water pressure inside and outside the enclosure. A submarine-like viewing corridor inside the protective structure allows visitors to see the inscriptions at close range while safeguarding the site for future generations.

Opened in 2009 after construction began in 2003, the Chongqing Baiheliang Underwater Museum is described by local authorities as the world's first underwater museum. It features a ground-level exhibition hall and an underwater viewing area, where visitors can see the ancient inscriptions through glass windows.

On Sept 9, Li You, a 43-year-old tourist from Anqing, Anhui province, visited with his family, marveling at the stone fish carvings and centuries-old inscriptions preserved underwater.

"We've long admired this historic city and came specifically to see this underwater museum," Li said, describing its design as futuristic. "Here, my family and I have witnessed how the ancients wisely observed and recorded the Yangtze's hydrology."

Baiheliang has grown increasingly popular in recent years. The museum welcomed more than 400,000 visitors last year, over twice its previous peak, significantly contributing to the cultural and economic development of Fuling, according to the museum.

Jiang Rui, curator of the museum, highlighted ongoing digital preservation efforts, including the establishment of "China's first early warning platform of underwater cultural heritage protection". This platform aims to address challenges such as underwater structure displacement and environmental changes.

Beyond its local significance, Baiheliang is central to a potential joint World Heritage bid with Egypt's Raoudha Nilometer. The proposed partnership highlights the achievements of two ancient civilizations in monitoring river levels, while demonstrating how modern conservation methods can protect their historical records.

The Raoudha Nilometer is an ancient structure built in 861 to measure the Nile River's water levels. It consists of a stone well with a central pillar marked for gauging the river's height. The readings helped ancient Egyptians anticipate the annual flooding of the Nile, which was vital to agriculture and the economy.

The 2026 Yangtze River Civilization Forum, held last month, lent further momentum to the initiative through a cultural exchange event dedicated to the project.

China and Egypt have held international symposiums and organized reciprocal visits for years to advance the preparations. The cooperation has also extended to public outreach: a joint documentary, When the Yangtze Meets the Nile, was broadcast in Arab countries, while a digital exhibition was presented in Egypt.

In July, a related event at the 48th session of the World Heritage Committee in South Korea received praise, strengthening the professional foundation and international support for the application.

As preparations continue, Dai Chuan, head of the World Heritage Application Office of Fuling's Culture and Tourism Commission, said the team would follow UNESCO guidelines and the directives of the National Cultural Heritage Administration.

"We are refining the application documents and will proceed in an orderly manner," he said.

Contact the writers at dengrui@chinadaily.com.cn