Jiuzhaigou Valley is a nature reserve in the north of Sichuan. It is known for its many multi-level waterfalls and colorful lakes, and was declared a UNESCO World Heritage Site in 1992. It belongs to the category V (Protected Landscape) in the IUCN system of protected area categorization.

    Jiuzhaigou's landscape is made up of high-altitude karsts shaped by glacial, hydrological and tectonic activity. It lies on major faultlines on the diverging belt between the Qinghai-Tibet Plate and the Yangtze Plate, and earthquakes have also shaped the landscape.  Its best-known feature is its dozens of blue, green and turquoise-colored lakes. The local Tibetan people call them "Haizi" in Chinese, meaning "son of the sea". Originating in glacial activity, they were dammed by rockfalls and other natural phenomena, then solidified by processes of carbonate deposition. Some lakes have a high concentration of calcium carbonate, and their water is very clear so that the bottom is often visible even at high depths. The lakes vary in color and aspect according to their depths, residues, and surroundings.