Ayers Rock was named for the Premier of South Australia, Sir Henry Ayers. It's also known by its Aboriginal name 'Uluru'. Ayers Rock is the world's largest monolith rising 318m above the desert floor with a circumference of 8 km. It's considered once of the great wonders of the world. It's located in the Kata Tjuta National Park, which is owned and run by the local Aboriginals. The Rock is arkose, a course-grained sandstone rich in feldspar. Depending on time of day and atmospheric conditions, the rock can dramatically change color, from blue to glowing red. It extends 3.5 miles beneath the surface. Approximately 500 million years ago it was part of the ocean floor at the center of Australia. Some believe there is a light source emanating at various times of the year. The Aborigines believe there it is hollow below ground, and an energy source which they call 'Tjukurpa' - the 'dream time'.