Olgas, group of tors (isolated weathered rocks) in southwestern Northern Territory, Australia. The Olgas are a circular grouping of some 36 red conglomerate domes rising from the desert plains north of the Musgrave Ranges. They occupy an area of 11 square miles (28 square km) within Uluru–Kata Tjuta National Park (established in 1958 as Ayers Rock–Mount Olga National Park) and culminate at Mount Olga, 1,500 feet (460 metres) above the plain and 3,507 feet above sea level. Mount Olga is the most westerly of Australia’s three giant tors; the others are Uluru/Ayers Rock and Mount Conner (Artilla). They were visited and named in 1872 after Queen Olga of Württemberg by the explorer Ernest Giles. Their Aboriginal name, Kata Tjuta, means “many heads.” The rocks offer visitors a constantly changing array of colour as the sun moves overhead and illuminates the luxurious vegetation in deep clefts between the domes.