Tepotzotlán sits north of Mexico City, close enough for a day trip but distinct enough to feel like a real change of pace. Its old centre is compact, colonial, and busy on weekends, with food stalls, craft vendors, and families spilling around the main square.
The reason to come is the former Jesuit college, now the Museo Nacional del Virreinato. It is one of Mexico's strongest museums outside the capital, and the church of San Francisco Javier gives the town a baroque centrepiece that would justify the trip on its own. Tepotzotlán also sits on the Camino Real de Tierra Adentro UNESCO route and carries Mexico's Pueblo Mágico designation.
If you have more time, add the nearby Arcos del Sitio, an 18th-century aqueduct in a rural park. The result is a simple but satisfying day: museum, church, plaza, lunch, and a bit of countryside.