Victoria Falls is the largest curtain of falling water on Earth, and the first thing you meet is not the water but the smoke. The Zambezi goes over a cliff on the border between Zambia and Zimbabwe, all 1,708 metres of it at once, into a gorge so narrow that the spray comes straight back up. It climbs hundreds of metres and is visible from tens of kilometres away. The people who lived here first called it Mosi-oa-Tunya, the smoke that thunders, and nothing has improved on the name. A forest trail runs the whole Zimbabwean rim, and the noise reaches you before the view does. Then the trees open and the falls are standing straight across the gorge. Around April, with the river in flood, the spray falls back on the path as steady rain and you finish the walk soaked.
By October the same cliff is bare black basalt, the river threading down it in separate streams. That is not the falls failing. It is what opens the rest of the place. From about September to December the water drops enough for Devil's Pool. A rock ledge at the tip of Livingstone Island, on the Zambian side, slackens the current just enough to let you swim to the very lip and look over. The same drop turns the Batoka Gorge below into big water, rafted between sheer basalt walls. A steel bridge crosses that gorge just under the falls, carries the border, and is where people jump with a rope on their ankles. From a light aircraft the whole thing makes sense: the unbroken front, and downstream a zigzag of empty gorges, each one a cliff the falls stood on before the river cut further back. Above all this the Zambezi is wide and calm around its islands, and boats drift it at dusk. Then, on the few nights around a full moon, the smoke does one last thing. It turns moonlight into a moonbow, a pale arc over the gorge in the dark, and almost nowhere else on Earth is wet enough to make one.