One continent, and almost every extreme on the planet: the driest non-polar desert on Earth and the largest rainforest, the highest navigable lake and the longest mountain range above sea level, the wettest place in the Americas and a salt flat so smooth that satellites use it to calibrate their instruments. The course starts with the land, because in South America the land explains nearly everything else. The Andes run 7,000 kilometres down the western edge, wringing the rain out of the Pacific air and leaving the Atacama behind them, while the same mountains feed the rivers that become the Amazon — a basin of six million square kilometres carrying a fifth of all the river water that reaches the sea. Then the countries, four episodes of them: Brazil, half the continent by land and by people; the Andean republics of Peru, Bolivia and Ecuador, where Quechua and Aymara are official languages and where the Inca ran an empire without a wheel or a written script; Colombia and Venezuela on the Caribbean shoulder; and the Southern Cone, where the pampas made Argentina rich and Chile stretches 4,300 kilometres down a coastal strip barely 180 kilometres wide. The last track is the people: the nations who were here first and the 400-plus languages still spoken, three centuries of Spanish and Portuguese rule, the Africans brought across the Atlantic and the Europeans, Japanese and Arabs who followed, and the cities where nine of every ten South Americans now live.