The didgeridoo is a wind instrument developed by Indigenous Australians of northern Australia at least 1,500 years ago and is still in widespread usage today both in Australia and around the world. It is sometimes described as a natural wooden trumpet or "drone pipe". Musicologists classify it as an aerophone. The instriment is traditionally made from Eucalyptus trees which have had their interiors hollowed out by termites or died of other causes. There are no reliable sources stating the didgeridoo's exact age, though it is commonly claimed to be the world's oldest wind instrument. Archaeological studies of rock art in Northern Australia suggests that the Aboriginal people of the Kakadu region of the Northern Territory have been using the didgeridoo for at least 1,500 years, based on the dating of paintings on cave walls and shelters from this period. A clear rock painting in Ginga Wardelirrhmeng, on the northern edge of the Arnhem Land plateau, from the freshwater period shows a didgeridoo player and two songmen participating in an Ubarr Ceremony