Uluru

Uluru is a large sandstone monolith rising from flat scrubland in central Australia's Northern Territory, within Uluru-Kata Tjuta National Park. Geologically it is an inselberg, an isolated remnant hill left standing after the erosion of a much larger mountain range that once covered the region. The rock began forming roughly 500 million years ago as sediment deposited in an ancient inland sea, was compressed into arkose sandstone rich in feldspar, and was later uplifted and tilted onto its side so that its original rock layers now stand nearly vertical. Iron oxidation on its exposed surface gives Uluru its distinctive red to orange color, though the sandstone beneath is grey. It rises 863 meters above sea level, about 348 meters above the surrounding plain, with a base circumference of roughly 9.4 kilometers.