Hailuogou is the eastern flank of Gongga Shan — at 7,556 m the highest mountain in Sichuan and the 'King of Sichuan' — and its draw is a glacier that descends unusually low, to about 2,850 m, through cloud forest and mist. Most glaciers in the world sit above the treeline; this one you can reach on foot or by cable car and stand beside.
The valley is organised into camps by altitude. Camp 1 at 1,940 m, 15 km from Moxi, is warm and forested with hot springs. Camp 2 at 2,580 m is the hot-spring camp, its pools set in old forest with steam drifting through the trees. Camp 3 at 2,940 m, by a glacial lake, is the classic place to watch the sunrise turn Gongga gold. Camp 4, reached by cable car, stands almost against Gongga itself, with the whole glacier spread out below.
Above it all is the Great Ice Fall, more than 1,000 m high and 1,100 m wide — bigger than Huangguoshu Falls by an order of magnitude — with the moving ice pushing rock and debris down the mountain behind its calm white face. The whole massif is a biodiversity hotspot, seven climate zones stacked from the gate to the summit, which is why the forest on the way up keeps changing.
Below the glacier is Moxi, the old town at the valley mouth on the tea-horse road, with Ming and Qing timber houses, a 1918 French Catholic church and the memory of the Long March — Mao and Zhou Enlai slept here in 1935 and held the Moxi Conference. It is the base, the bus stop and the place to eat, and it is worth a slow afternoon of its own.