Natural Features & Ecosystems
The interface between the sunlit and nether worlds
Mammoth Cave, by far the world's longest known cave system, is the heart of the South-Central Kentucky karst, an integrated set of subterranean drainage basins covering more than 1,050 square kilometers – 400 square miles. Atop this labyrinth is a biologically diverse set of ecosystems inextricably interlinked with the ecosystems underground. This physiographic province, with Mammoth Cave National Park at its core, was declared an International Biosphere Reserve in 1990.