Atzitzintla

Atzitzintla is the seat of the municipality of the same name in eastern Puebla, on the foothills of Citlaltépetl, Pico de Orizaba. Its Nahuatl name translates as "a little water below". The town stands at about 2,670 m and had 3,524 people in 2020. Nahua groups founded it before the Spanish conquest, though there are traces of occupation in the region from the Middle Preclassic; until the 19th century it depended on San Andrés Chalchicomula, and in 1895 it became a municipality in its own right.

The Large Millimeter Telescope Alfonso Serrano, built by Mexico's National Institute of Astrophysics, Optics and Electronics (INAOE) and the University of Massachusetts, stands in this municipality on the summit of the Sierra Negra volcano and was inaugurated on 22 November 2006. The territory, about 94 km², runs from the Llanos de San Andrés plateau at about 2,500 m up the southern slopes of Sierra Negra and Citlaltépetl; its northern tip touches the Pico de Orizaba glacier, an area of permanent snow that is shrinking. To the east it borders the Veracruz municipalities of La Perla, Mariano Escobedo and Maltrata.

It is one of the driest parts of Puebla, with about 400 mm of rain a year, because the Sierra Madre Oriental blocks the clouds from the Gulf; the mean temperature on the plain is around 12 °C. The slopes carry fir, pine and pine-oak forest, home to raccoons, bobcats, owls and rattlesnakes, while the plain is given over to farming. Almost the whole municipality drains toward the Papaloapan and the Gulf of Mexico.