The Jenolan Caves are the most spectacular limestone caves in Australia. Located in the Blue Mountains, nine show caves are open to the public with underground rivers, breathtaking lighting and incredible cave formations. They were discovered in 1840 by James and Charles Whalan and were named Jenolan, Aboriginal for high mountain, in 1884. The caves developed around 450 million years ago when Australia's eastern coastline was further inland. Coral atolls formed around a series of partially submerged volcanoes that became incredible limestone caves when compressed. The complex system is one of the largest underground cave systems in the world.