Wikipedia
Cuexcomate is an inactive geyser in Puebla city, Puebla state, Mexico. The sinter cone that the geyser built up around its vent is tall and has a diameter of . A central crater within the cone is up to wide and deep (extending below ground level).
Historically, Cuexcomate has been cited that the geyser was formed before the 1064 eruption of the Popocatépetl, an active volcano and the second highest peak in Mexico, which likely activated geothermal spring circulation that cut upward through Mesozoic limestone and deposited the geyser and the springs around it. The geyser's rock composition is 99% calcite, differing thus from typical silica sinter deposits.
Cuexcomate has been mistakenly called 'The Smallest Volcano of the World' because of the popular belief that it was indeed a volcano, based only on the shape of the structure; however, it is not a volcano. Today, there is a metal spiral staircase that allows tourists to descend into the excavated interior of the structure, where cultural events are occasionally performed.
The name is from Nahuatl for "clay pot" or "place to keep".