Baiheliang, a natural sandstone ridge, stands in the water of Yangtze River, north to Fuling town, Chongqing city.This sandstone ridge was named the Baiheliang (While Crane Rocky Ridge) since flocks of birds, especially cranes, used to perch on or fly over it in the ancient time.Baiheliang, whose top elevation is about 138m, has been submerged under water until the end of winter when the river is low-flow.On Baiheliang many inscriptions had been engraved in the ancient time, which recorded the water levels of 72 low-flow years of Yangtze River since the Tang Dynasty (763).Baiheliang inscriptions could be fairly claimed as the No.1 well-preserved Ancient Hydrometric Station and the rare underwater inscription in the world.These inscriptions emerge from water once every three or five years.The Baiheliang inscription is the national-grade key cultural relic preservation unit.It is significantly valuable in science, history, art, etc.Unfortunately, Baiheliang ridge will be submerged into the water forever when the normal storage level of TGPs reservoir rises to the elevation of 175m.To preserve these underwater cultural relics really and integrally, the in-situ "No-Pressure Vessel" protection scheme is proposed, which comprehends the multidiscipline techniques, such as the cultural relic, water conservancy, architecture, civil, navigation channel, submarine and special devises.By this protection scheme, the Baiheliang Ridge is preserved in-situ and could be visited in its intact state after the protection project is completed.The total construction area is 8 433 square meters and the total investment is 0.19 billion RMB.The constructions of the Baiheliang in-situ protection project began on Feb.13, 2003, finished and open on May 18, 2009.It is the only underwater museum that is constructed in the over-40-meter-deep water in the world.It provides a successful paradigm for the cultural relic in-situ protection under water, glorifying the great Three Gorge Project of China.