Three Gorges primarily famous for its scenery, the Three Gorges region is also historically and culturally important in China. Many settlements and archaeological sites are in danger of being submerged by the rising reservoir of the Three Gorges Dam. Due to the lithological conditions of its different regions, the valleys of the Three Gorges are narrow in some areas and broad in others. Most narrow valleys occur in regions where there is limestone, which is relatively hard and resists erosion. However, water can flow along deep vertical fractures, eroding underneath. As the limestone bed is gradually undercut, parts of it fall into
Three Gorges Reservoir Region narrow and where the geography is complex. The mountainous areas represent 74% of the region only with 4.3% plain area in the river valley and 21.7% hilly area. The climate of the reservoir region of the Three Gorges Project is the subtropical monsoon climate. Its location is in the transfer between the northern temperate zone and the subtropical zone, where it is hot and it rains a lot with the annual rainfall of about 1100 mm. The valley of the Three Gorges Reservoir Region below 500 m has an annual temperature 17–19 °C and, with the frost-free period annually lasts