The Makgadikgadi Pans are the floor of a sea that dried up: sixteen thousand square kilometres of salt crust in Botswana with almost nothing standing on it. Guided quad bikes run far out onto the open pan, where the ground crunches under you like packed snow. Then the guides switch the engines off. There is no hill, no tree and no building anywhere for a sound to come back from, so the silence is total. The one thing that breaks the flat is Kubu Island, a granite ridge a kilometre long lifting ten metres out of the white. Old baobabs grip the rock, and dry-stone walls and cairns run along its spine. At last light the stone goes orange and the pan around it turns pink.
On Kubu's windward side the granite is polished smooth, with terraces of rounded pebbles below it. That is a beach: the pebbles were worked round by waves breaking against this rock, before the rivers feeding the lake were tilted away and it evaporated. Out on Ntwetwe, Chapman's Baobab was the only landmark on the crossing, twenty-five metres round, and travellers left letters in its hollow for the next wagon. It turned out to be six fused stems from three generations, the oldest about 1,400 years, and it came down in 2016. You walk the whole ring of the trunk at ground level now. From July to October the zebra are back on the Boteti, the only open water for miles, filing down the steep banks in thousands while lions work the treeline. The rains turn them round again, out to the mineral grass at the pan's edge, and in a wet year flamingos nest on Sowa's open mud. At the edge, habituated meerkat clans let you sit at their level while one stands sentry. There is nothing to pitch a tent against and nothing solid to peg into, so bedrolls go straight down on the salt, and you lie at ground level with the horizon unbroken all the way round.