Almost every canyon this size is bare rock. Blyde River Canyon, 800 metres deep on the edge of the Drakensberg escarpment in South Africa's Mpumalanga, is green the whole way down. Its red cliffs rise out of forest, and the river at the bottom runs through bush rather than desert. It is warm and wooded enough down there that every primate species in South Africa lives in this one canyon, from bushbabies to the samango that keeps to the canopy. You see all of it from above. The rim road, the Panorama Route, is strung between lookouts. The picture people come for is the Three Rondavels: three round flat-topped peaks named after the thatched huts of the region, and by the people already here after a chief and his three wives. Late afternoon is their hour, when the sun comes round far enough to strike the faces head-on instead of leaving them flat. From the platform you can pick out their reflection in the dam far below, where hippos and crocodiles lie unseen from the rim.
At Bourke's Luck Potholes you stand on footbridges and look straight down into shafts drilled clean through the pale rock, water still at the bottom. What cut them is pebbles caught spinning in the current, and they are still cutting. It is also where the Treur runs into the Blyde, sorrow into joy, the two rivers named against each other by the Voortrekkers. The potholes carry the name of Tom Bourke, a prospector who pegged a claim here in the 1880s reckoning the shafts would trap gold washing down from the hills. They did not. A few minutes off the road, Berlin Falls slides down a rust-red chute into a dark green pool. The last stop is God's Window, a railing where the escarpment falls sheer to the Lowveld, the hot plain running on to Kruger and Mozambique. Then a path behind the lookout climbs a few minutes into mountain rainforest, dripping wet, with the whole dry country still at your back.