In July, the city of Chongquing, in southwest China, resorted to opening up air raid shelters built during WW2 – amid large-scale bombing from Japan – to shelter citizens from a very different threat: a 10-day streak of weather above 35C (95F).

This year, the strategy seems more prescient than ever. But on a summer's day, Coober Pedy – loosely translated from an indigenous Australian term that means ' white man in a hole' – needs no explanation: it regularly hits 52C (126F), so hot that birds have been known to fall from the sky and electronics must be stored in fridges. In the winter, this troglodyte lifestyle may seem merely eccentric. In some neighbourhoods, the only signs of habitation are ventilation shafts sticking up, and the excess soil that has been dumped near entrances. In this corner of the world, 60% of the population inhabits homes built into the iron-rich sandstone and siltstone rock. Many of its little peaks are the waste soil from decades of mining, but they are also evidence of another local specialty – underground living. These are the first signs of Coober Pedy, an opal mining town with a population of around 2,500 people. Every now and then, there is a white pipe sticking up from the ground next to one. Around them, the landscape is utterly desolate – an endless expanse of salmon-pink dust, with the occasional determined shrub.īut as you venture further along the highway, more of these mystery constructions emerge – piles of pale earth, haphazardly scattered like long-forgotten monuments.

On the long road towards central Australia, as you travel 848km (527 miles) north from Adelaide's coastal plains, is a scattering of enigmatic sand-pyramids.

Tricky towers price history