It’s a sudden place. The rolling grasslands of the South Dakota plains may end, and the Badlands begin, in a matter of inches. My old friend Bob Henderson was once chasing a coyote with his pickup truck over the open rangeland southwest of Kadoka. The coyote ran up a long slope and vanished over the horizon with Bob hot on his trail. At the last moment Bob realized there was something wrong about the sky up ahead and turn sharply, passing just a few yards from the brink of a hundred-foot cliff.

John Madson, “South Dakota’s Badlands: Castles in Clay”, National Geographic April 1981.