4th Time's the Charm: Climbing El Potrero Chico and Road-Tripping to Punta de Mita From a Border Office Standoff in Coahuila to a Music Video Shoot in Nayarit — This Is the Mexico Trip That Finally Worked El Potrero Chico, Nuevo León. Where limestone goes to be extraordinary and families go to discover their limits. There is a specific kind of humility that comes from being turned away at the same international border twice. The first time, the Mexican border officer at Piedras Negras informed us that Base Camp — our converted school bus, our beloved rolling home — was registered as a "bus" and therefore could not receive a Temporary Import Permit (TIP). "No se puede," she said, with the serene finality of someone who has delivered this news before and is entirely comfortable delivering it again. We drove thousands of miles back to Maine to re-register it as an RV. We spent a summer working. We came back. The second time was the...