Huanglong Cave — Yellow Dragon Cave — is a karst cave in Wulingyuan District, the limestone underworld beneath the district's sandstone pillars. Its mapped system runs about 15 kilometres through four levels, holding thirteen chambers, ninety-six passages, three underground waterfalls and two underground rivers, one of which carries visitors by boat. Rated a national 4A scenic area and run since 1997 by a Beijing company, it passes a million visitors a year; its entrance square, restored ecology and concert hall make it a managed landscape as much as a cavern.
Huanglong Cave runs fifteen kilometres under the sandstone district of Wulingyuan, and one of its two underground rivers carries visitors by boat. The cave explains the other half of the district's geology — and the million visitors a year explain its management.