An illustrated account of the geological and natural history of one of Australia’s many deserts. This is a story of ancient subterranean rivers that left vast caverns with crystal clear lakes beneath the now treeless plain, of giant marsupials that once roamed there and how the arrival of man 40,000 years ago contributed to changes in the flora which led to the ultimate demise of the megafauna. The talk will also include the results of the speaker's 1960/61 expedition to some of the caves when remains of the extinct fauna were found and the first ever attempt to SCUBA dive in the lakes was made.