Rincón de la Vieja National Park, straddling the Guanacaste Cordillera, is invariably a favorite of those fortunate few people privileged enough to have visited the majority of parks in the system. Highlights of this park include six different life zones, abundant wildlife, gorgeous waterfalls, fascinating geothermal features and an active volcano.

One of the most unique and easily observed aspects of this park is an area known as Las Pailas, a 50 ha. sector on the southern slope of the volcano with numerous kinds of geothermal activity. Bubbling, boiling hot mud springs, sulfur springs, steam vents, and fumaroles are all present in this relatively small area at the base of the volcano.

For those in good physical condition, a hike from the Las Pailas ranger station to the volcano's summit makes for a rigorous full day outing. The walk starts out through a magnificent stand of tropical moist forest where the most striking trees are strangler figs seen in every phase of the process of enveloping the doomed host tree. As the trail continues upwards it enters premontane wet forest and the trees become smaller and covered with epiphytic vegetation.

The last hour and a half (or more) of the hike is on steep, exposed rock rubble that has resulted from past eruptions. Cairns mark the way to the summit since this part of the climb is frequently in the clouds.

To get there: From Liberia, take the Inter-American Highway north about five kilometers, turn right at the village of Cereceda and continue on for 23 kilometers (past Hacienda Guachipelín and Hacienda Rincón de la Vieja) to the Las Pailas ranger station.

Climate: Around the Las Pailas area the temperatures are quite warm (scalding if you manage to fall into one of the geothermal features) and the typical Guanacaste weather pattern prevails. As you go up the slopes of the volcano, the conditions get progressively cooler and wetter.

History: The name Rincón de la Vieja means "the old lady's nook" and is attributed to indigenous people of the Guatuso tribe living on the eastern side of the volcano who believed that an old witch lived on top of the mountain and would send columns of smoke into the air whenever she got annoyed.

Indeed, the active crater which bears this name periodically lets off steam (and large quantities of ash, too). Since 1863, there have been at least eight episodes of intense volcanic activity, the latest one in 1991.