Yachts are seen in waters over the Sanya River estuary passage project in Sanya, south China's Hainan Province, Dec. 5, 2025. The Sanya River estuary passage project undertaken by China Railway 20th Bureau Group was successfully drilled through on Friday. This 3.118-kilometer underwater tunnel, the first of its kind in Sanya, is expected to further optimize the urban spatial layout of the city, and facilitate the development of the Hainan Free Trade Port. (Xinhua/Zhao Yingquan)
A staff member works at the construction site of the Sanya River estuary passage project in Sanya, south China's Hainan Province, Dec. 5, 2025. The Sanya River estuary passage project undertaken by China Railway 20th Bureau Group was successfully drilled through on Friday. This 3.118-kilometer underwater tunnel, the first of its kind in Sanya, is expected to further optimize the urban spatial layout of the city, and facilitate the development of the Hainan Free Trade Port. (Xinhua/Zhao Yingquan)
Staff members celebrate tunnel drill-through of the Sanya River estuary passage project in Sanya, south China's Hainan Province, Dec. 5, 2025. The Sanya River estuary passage project undertaken by China Railway 20th Bureau Group was successfully drilled through on Friday. This 3.118-kilometer underwater tunnel, the first of its kind in Sanya, is expected to further optimize the urban spatial layout of the city, and facilitate the development of the Hainan Free Trade Port. (Xinhua/Zhao Yingquan)
A staff member works at the construction site of the Sanya River estuary passage project in Sanya, south China's Hainan Province, Dec. 5, 2025. The Sanya River estuary passage project undertaken by China Railway 20th Bureau Group was successfully drilled through on Friday. This 3.118-kilometer underwater tunnel, the first of its kind in Sanya, is expected to further optimize the urban spatial layout of the city, and facilitate the development of the Hainan Free Trade Port. (Xinhua/Zhao Yingquan)
