The Zaqu River, the main headwater of the Mekong, flows through the valleys south of Nangqen before crossing into Tibet and eventually becoming the great river that runs through Southeast Asia to the South China Sea. Here it is young, cold, and fast, cutting through gorges of pale limestone beneath ridges that hold snow well into summer.
The landscape around the upper Mekong is one of the more dramatic in southern Qinghai — deeply incised valleys alternate with broad grassland plateaux where yak herders set up seasonal camps. There are no organised tours; exploring this area means hiring a driver and being flexible about roads. The best approach is to hire a vehicle in Nangqen for a full-day or overnight circuit into the river valleys to the south.