Fifteen Nepali artists were closeted for a month with a heap of 1.5 tonnes of trash picked up from Mount Everest. When they emerged, they had transformed the litter into art. The 75 sculptures, including one of a yak and another of wind chimes, were made from empty oxygen bottles, gas canisters, food cans, torn tents, ropes, crampons, boots, plates, twisted aluminium ladders and torn plastic bags dumped by climbers over decades on the slopes of the world’s highest mountain.