Ouzoud Falls tumbles 110 metres down three broad tiers of red limestone. It is the tallest waterfall in Morocco and a rare rush of water in a country better known for its deserts. Its name comes from the Amazigh word for grinding grain, and the mills that earned it that name are still working: small stone flour mills turn on the same stream that feeds the drop, as they have for generations. The river here is the El-Abid, which means "river of slaves" in Arabic. It has cut a deep gorge through olive groves that climb the canyon walls in silver-green terraces. In the afternoon, when the sun swings low into the valley, its light catches the spray at the base, and a rainbow hangs in the rising mist almost every day.
A steep, switchbacking path drops through the olive terraces to the green pool at the foot of the falls. It passes cafés cut into the rock where the air smells of mint tea and grilled meat and the roar of the water never lets up. Even at the height of a Moroccan summer the spray keeps the gorge cool, and the pool stays cold enough to gasp at. Above the water, troops of wild Barbary macaques move through the trees. They are the only monkeys living outside Asia and the last primate in Africa north of the Sahara. The falls sit about 150 kilometres from Marrakesh, close enough for a long day trip. By early afternoon the clifftop viewpoints fill with visitors who are bussed in for a few hours before the long road back to the city, so by dusk the gorge is left to the water, the mills and the monkeys.