Geoscience Australia photo (fair use policy)
Uluru is a great block of uptilted sandstone in the heart of Australia's Outback. This region may be the world's best-developed peneplain, and Uluru its best-known monadnock.
OK, I'll explain that. A peneplain is a surface that has eroded to almost perfect flatness, and a monadnock is an isolated rocky remnant of erosion left standing above it. Peneplains are an old-fashioned concept, and you don't see the word used much in the literature. The idea, first put forth by William Morris Davis in 1889, is that landscapes evolve from their young, rugged form to an end stage approximating a perfect plane. In most places this concept is irrelevant because Earth changes too much, interrupting the pristine process. Monadnocks are named for Mount Monadnock, in southern New Hampshire, which is a lovely place and an excellent example of the species.