Grutas de Lanquín
Portions of the Grutas de Lanquín, a system of caves cut through by underground rivers, are easy to explore. The first 30 minutes of the hour-long hike consist of a trail with iron railings to help you keep your footing among the huge stalagmites. Things get hairier toward the end, and you'll want an experienced guide who knows exactly how to help you navigate the path. Visit toward sunset and you'll see thousands of bats leave their dwellings and head for the starry night sky. Entering the caves is worth it, despite the garish labels painted on the rock formations. You could probably figure out yourself what the formations are, but signs point them out to you anyway: sapo (toad), oveja (sheep), tigre (tiger), or señora (woman).
You'll get wet and dirty, so wear old clothes. The interiors of the caverns are illuminated, but you'll appreciate a small flashlight.
