Todra Gorge is a crack in the High Atlas above Tinghir, in southeastern Morocco, where limestone walls 160 metres high close to about ten metres apart. A shallow, ice-clear river runs along the floor between them. There is no gate and no approach walk. A paved road runs into the narrowest part, so you park beside the stream and carry on along the flat stony floor on foot. The sky closes to a bright ribbon overhead and footsteps come back off the rock. The light on the cliffs shifts every few minutes as the sun moves across that strip. The water is High Atlas snowmelt, cold enough to numb your feet while the desert above sits in the mid-thirties, and you cross it on flat stones. In spring the melt swells it and the narrows run green; a storm upstream can put the whole floor under water within the hour.
The walls carry their own population. The limestone here has been bolted from bottom to top for fifty years, ever since Spanish climbers put up the first lines in 1976. One Dutch team added about 120 routes in a single winter. The faces are minutes from the road, so through the cold months climbers hang a hundred metres up while you walk underneath them. On the warm shaded stones by the water a common chameleon may be inching along, swivelling one eye at a time. Blue rock thrushes and black wheatears cross the bare rock above. Downstream the gorge opens out and the Todgha spreads into a long oasis of date palms and fig trees, small plots worked by hand. Mud-brick kasbahs and villages are strung along it, with footpaths between the gardens. Families have farmed this thread of water for centuries, and every share of it is divided among them by old custom. The spring on the gorge floor is held to be the one exception, free for anyone to drink, and the small fish that live in it are left alone.