The Museo del Valle de Tehuacan is the best single reason to spend more than an hour in the city. It covers the extraordinary archaeological importance of the surrounding valley — one of the most significant regions in the history of human agriculture. It was here, in dry caves and rock shelters, that MacNeish's excavations in the 1960s found evidence of the gradual domestication of maize, squash, chilli, and other Mesoamerican crops over several thousand years.
The museum displays actual seeds, plant remains, and artefacts from the cave sites alongside a clear explanation of how and why the dry climate of the Tehuacan Valley preserved organic material that would have rotted elsewhere. The collection also covers the later pre-Columbian cultures of the region — the Popoloca, Nahua, and Mixtec peoples who inhabited the valley before the Spanish conquest. The exhibits are in Spanish, but the archaeological material speaks for itself. Located in the Ex-Convento del Carmen; open Tue–Sun 9:00–17:00.