San Pedro is a dust-coloured village at 2,400 metres that exists entirely to sell the desert around it: the Valle de la Luna at sunset, the Tatio geysers at dawn in minus ten, the altiplano lagoons, and the crossing to Uyuni.
It is also one of the best places on earth to look at the sky. The air is dry, the altitude high and the nearest city hours away, which is why the professional observatories are here and why the amateur ones sell tickets.