ON THE ROAD — Troglodytes get a pretty bad rap in popular culture with the common cartoon depiction being a creature half hippie/half sasquatch squatting in a dingy cave with a sooty ceiling. There’s nothing dingy about the underground homes of Coober Pedy’s cave dwelling opal miners who discovered the thermal advantage of living underground in a searingly hot desert. Visitors can stay in a number of underground motels and ours was called, quite descriptively, the Underground Motel. Our room was at the end of a somewhat luridly appointed hallway — all carved out of the soft sandstone. We enjoyed a very comfortable overnight stay with all modern conveniences. In China some 30million people still live underground.

ON THE ROAD — About 700km south of Alice Springs the gibber landscape is suddenly dotted with conical mounds — looking like the work of giant ants. These ants are rugged Australians who for 100 years have been sinking mine shafts in the hope of rich reward created millions of years ago. About 150 million years ago an ocean covered the Coober Pedy region. As the sea water receded silica solutions were carried down to be deposited in cavities, faults and fractures. Over time those deposits have been transformed into opal. The Coober Pedy opal fields were discovered in 1915 by a group of men looking for gold. 100 years later Coober Pedy produces 85% of the world’s opal supply.