Approximately 17 kilometers south of Pito Solo, at kilometer marker 140, are the Cuevas de Taulabé (8 a.m.–4 p.m. Mon.–Fri., until 5 p.m. Sat.–Sun., US$2), which have been mapped and explored to a depth of 921 meters without hitting the bottom, though it is believed that exits from the caverns exist as far away as Lago de Yojoa [1], Santa Bárbara [2], and Copán [3].
The first 300 meters of the cave have been lit and have railings and steps, taking anywhere from 25 minutes to an hour to explore, depending on your pace. Beyond that, bring a flashlight and watch your footing.
It might be best to hire a guide for exploring beyond the main path, as it’s easy to get lost; rates are negotiable, typically US$3–4 for an hour. Ask about the legendary bandito who hid out in the Cuevas de Taulabé for months. Locally made honey is sold along the highway near Taulabé.
Links:
[1] http://www.moon.com/destinations/honduras/central-honduras/lago-de-yojoa
[2] http://www.moon.com/destinations/honduras/central-honduras/santa-barbara-and-vicinity/santa-barbara
[3] http://www.moon.com/destinations/honduras/western-honduras/copan