Cascada Cola de Caballo is the easy nature classic south of Monterrey, near the Pueblo Magico of Santiago. The waterfall drops in a long white ribbon that gives it the "horse tail" name, and the surrounding ecotourism park makes the visit straightforward for families and first-time visitors.
It is popular and can feel busy, but it still belongs on the Monterrey list because it gives a quick taste of the greener mountain country beyond the city. Pair it with Santiago's centre or the nearby reservoir for a fuller day out.