Rincon de la Vieja National Park is an area of high geothermal activity. Huge swathes of the park are located on the slopes of the Rincon de la Vieja volcano, considered one of the more active volcanoes in Costa Rica, and the forces at work beneath the surface affect not just the volcano, but also the park's bubbling mud pools.
Thermal springs offer the perfect bathing opportunity and you can cool off afterwards by diving into one of the deep plunge pools carved out over the years by waterfalls and cascades.
Horse riding is the perfect way to reach these isolated spots while looking out for the natural flora and fauna. With over 200 species of bird as well as armadillos, squirrel monkeys and tapirs the rainforest here is as biologically rich as many of the more popular eco-tourism destinations elsewhere.