Nature: Kaka Tshering loops a piece of frayed jute rope around a 150-kilogram boulder. A handful of his fellow workers line up on either end and pull the rope taught. “Shochi, Shoni,” the workers call in unison, as they heave. Their voices are raspy from the 4,400-metre altitude and moist, cold air. “Put your strength together.” After rocking a couple of times, the boulder rolls over and the labourers tumble backwards. Their cries are drowned out by the furious work around them as more …