Wucaichi: Due to the karst landform, the water in Jiuzhaigou Valley looks mainly blue and green through refraction. Wuhuahai: The same reason as above, but the vegetation around Wuhuahai is richer than Wucaichi, and the plants all grow on the mountains near Haizi. In autumn, different trees may have different color changes, some are green, some are green, and some are green. Yellow, red... reflected in the water, they look colorful and beautiful.