Dianchi is the eighth largest freshwater lake in China and the dominant geographical feature of the Kunming basin — a 300-square-kilometre body of water immediately south of the city, ringed by mountains and once the centre of the Bronze Age Dian civilisation. From the top of the Western Hills the lake stretches almost out of sight.
The lake itself is heavily polluted and not for swimming, the result of decades of industrial growth on its northern shore; clean-up efforts since 2010 have made measurable progress. The interest is on the shoreline: the Yunnan Nationalities Village on the eastern side, the wetland parks at Haigeng on the north, and the Caohai marshes where the gulls feed in winter. A new walking and cycling path runs around almost the entire perimeter.