Charyn Canyon opens without warning in the flat steppe of southeastern Kazakhstan, three hundred metres deep, and the ground gives no hint of it until the last few steps. Then the whole Valley of Castles is below you: three kilometres of red wall eroded into rows of towers, spires and ramparts, standing in ranks like a city nobody built. The rim is the only place you see them that way. Each tower is still there because it is capped, a tougher layer sitting on a column of soft lake sediment and shielding it while everything around gets washed and blown away. The colour keeps its own hours. In the hour after sunrise and the hour before sunset the walls burn red; by the middle of the day the same rock has flattened to a pale grey-pink.
Twenty kilometres downstream the park holds something else entirely. A forest of Sogdian ash lines the river floodplain at Sarytogay, the last grove of its kind in Kazakhstan. They are trees left over from a much wetter age, hanging on because their roots reach the river's groundwater while the land above has gone to dry steppe. It is a separate drive, and the change is abrupt: shade, birdsong and leaf litter underfoot, minutes away from bare desert. Back at the Valley of Castles, a wide track takes you down from the rim and threads the floor, the walls closing to eighty metres apart and opening out again. Up close the rock is layered like pastry, soft pale sandstone stacked on dark, hard lava, and the lava takes over completely as you near the bottom. There is no shade down there at all. The track ends at the Charyn itself, willows and cold green water, and from the floor the canyon is one wall at a time rather than a city. The river that cut all of this turns out to be a small one.