You will have to go right to the end of Zechawa Valley at 3,100m/10,170ft above sea level (the highest point to which the park shuttle goes) to see this crescent-shaped lake. Some 5km/3mi long, 600m/1,968ft wide and 100m/328ft deep, it is the biggest lake of Jiuzhaigou Park. Its inky black waters are fringed by thick woodland which stretches up to the summit, snowbound most of the year. In winter, the lake is covered in a layer of ice, up to 60cm/23 inches thick.