Kata Tjuta, also known as The Olgas, are a group of large domed rock formations (bornhardts) in Kata Tjuta National Park, Northern Territory, Australia. The 36 domes that make up Kata Tjuta cover an area of 21.68 square kilometres and are composed of conglomerate, a sedimentary rock consisting of cobbles and boulders of varying rock types including granite and basalt, cemented by a matrix of sandstone.