Mark Grundon, an AMGA-certified rock guide, works the limestone of El Potrero Chico from a base in the village of Hidalgo, an hour north of Monterrey.
The speciality is the step up to multi-pitch — the Potrero's long bolted routes are where many climbers do their first big wall — along with beginner classes and self-rescue courses. The longest days go up 600-metre lines such as Time Wave Zero. He can arrange lodging and pick-up from Monterrey airport.
The phone is a US (Vermont) number; email is the surer route.