A wind that tastes of dust and distant rock greets you as the convoy leaves Cairo behind, the city’s mosaic of heat and traffic giving way to long ochre flats. By midafternoon the landscape shifts — black volcanic ribs rise from the sand and the desert seems to take a breath. On day one you climb dark dolerite hills in the Black Desert, explore El-Haiz’s palm springs and stand beneath the crystalline teeth of Crystal Mountain before the White Desert opens like a planetarium of stone, where mushroom-shaped chalk formations catch the light and the night sky presses down in a wash of stars.