Two geodesic domes on the northern edge of town, holding a private collection of meteorites — most of them found in the Atacama itself. The desert is the best meteorite-hunting ground on the planet for a dull but excellent reason: nothing rusts here and nothing grows over anything, so a rock that fell out of the sky ten thousand years ago is still lying on the surface where it landed, looking exactly like a rock that fell out of the sky.
The visit is a guided circuit of about 45 minutes, in Spanish or English, with an audio guide and a handful of specimens you are allowed to pick up. Holding a piece of iron-nickel core from a shattered asteroid is a better argument for the place than any label. The explanations of how meteorites are classified and how you tell one from an ordinary stone are genuinely good, and short enough not to become a lecture.
It is small, it is privately run, and the entrance fee is modest. Set against the Museo Gustavo Le Paige it is the lighter of the two museums, and it works well as an hour indoors in the middle of the day when the sun makes anything else unappealing.