Spelunkers shouldn’t miss the El Boquerón cave, 20 kilometers northeast of Copán Ruinas  on the highway to San Pedro Sula . The Río Amarillo runs through the cave, so visits are best December–April or you may be forced to go for a swim. Almost two kilometers long, it’s filled with stalactites, stalagmites, and bats.
Guides  to the cave (recommended) can be easily found in Copán Ruinas. The Asociación de Guías Copán offers a day trip to the spectacular caves for about US$60 per person, which includes transportation and a meal.
To get to El Boquerón, follow the highway past Santa Rita  up a hill called La Carichosa, then look for a dirt road turning left. Ask for El Boquerón (The Big Mouth), about an hour’s walk from the highway turn.