The 57-square-km (22-square-mi) Poás Volcano National Park (Parque Nacional Volcán Poás) protects epiphyte-laden cloud and elfin (small-tree) forest near the summit as well as a blue-green crater lake and the volcano's massive active crater. The main crater, nearly 1½ km (1 mi) across and 1,000 feet deep, is one of the largest active craters in the world. The sight of this vast, multicolored pit with smoking fumaroles and a gurgling, gray-turquoise sulfurous lake is captivating. All sense of scale is absent here, as the crater is devoid of vegetation. No one is allowed to venture into the crater, or walk along its edge.
The peak is frequently shrouded in mist, and many who come here see little beyond the lip of the crater. Be patient and wait awhile, especially if some wind is blowing—the clouds can disappear quickly. The earlier in the day you go, the better your chance of a clear view. Aim to get there before 10 AM. If you're lucky, you'll see the famous geyser in action, spewing a column of gray mud high into the air. Poás last had a series of major eruptions in 2006; at any sign of danger the park is closed to visitors. It can be very cold and wet up top, so dress accordingly. If you come ill equipped, you can duck under a sombrilla de pobre (poor man's umbrella) plant, the leaves of which grow to diameters of 4 to 5 feet.
The park has a paved road that leads from the visitor center to the edge of the active crater, from which two trails head into the forest. The second trail, on the right just before the crater, winds through a thick mesh of shrubs and dwarf trees to the eerie but beautiful Laguna Botos (Botos Lake), which occupies an extinct crater. It takes 30 minutes to walk there and back. Note that Volcán Poás is a popular spot and gets quite crowded, especially on Sunday. It's not the place to go to commune with nature in solitude, but it is definitely worth seeing. The large visitor center has a scale model of the park, a display on vulcanology, a modest gift shop, and a cafeteria that serves hot coffee, perfect for those chilly afternoons.
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