The Makgadikgadi Pans are the salt floor of a vanished inland sea in the Central district of Botswana, 16,000 square kilometres of white crust flat enough to show the curve of the Earth, with a granite island of ancient baobabs standing out of them, and they are crossed by quad bike, slept on under an empty horizon and visited for the zebra migration and the meerkats at their edge. The lake that filled this basin was one of the largest in Africa, and a study of 2019 argued that every living human descends from a population that lived in the wetland it left behind 200,000 years ago; Kubu Island is a granite ridge a kilometre long lifting ten metres out of the salt, with old baobabs gripping the rock, low dry-stone walls and cairns along its spine, and on its windward side the granite polished smooth above terraces of rounded pebbles, a fossil beach, the old shoreline of the lake. Beyond the last baobab the crust runs featureless to the horizon, and the guided quad bikes head far out onto it, where the ground crunches like packed snow and the bedrolls go straight down onto the salt at night, with nothing to pitch against.
Chapman's Baobab, 25 metres around, was the post office of the explorers, who left letters in its hollow for the next wagon to carry on, and its six fused stems lie where they came down in 2016, walked around at ground level. Habituated meerkat clans near the pan's edge let visitors sit at eye level while a lookout stands sentry, and when the pans dry out the zebra migration falls back on the Boteti river, the only open water for miles, returning to the mineral-rich grass at the pans' edge with the first rains; flamingos nest on Sowa Pan only in a wet year, when the rain floods it deep enough. The dry-season sky holds the Milky Way over an empty rim. Makgadikgadi is a sea that became salt, and the horizon is the only thing on it.