This small museum on Santiago Tuxtla's main plaza focuses on the pre-Columbian peoples that inhabited this region from 1600 BC to around AD 1200, with a particular emphasis on the Olmecs, Mexico's first known major civilization. Artifacts include a Totonac effigy of a woman who died in childbirth, ceramic plates used in human-sacrifice ceremonies on the Isla de Sacrificios, Olmec stone carvings (including a colossal head), a monkey-faced hacha (ax) with obsidian eyes, and a Tres Zapotes altar replica.
There's also an interesting Spanish colonial room, with impressive suits of armor (including one with a skull-like visor) and a bust of poor Cuauhtémoc, the last Aztec emperor. Sadly, there's no labeling in English.