The broad, well-vegetated edifice of Poás, one of the most active  volcanoes of Costa Rica, contains three craters along a N-S line. The  frequently visited multi-hued summit crater lakes of the basaltic-to-  dacitic volcano, which is one of Costa Rica's most prominent natural  landmarks, are easily accessible by vehicle from the nearby capital  city of San José. A N-S-trending fissure cutting the 2708-m-high  complex stratovolcano extends to the lower northern flank, where it  has produced the Congo stratovolcano and several lake-filled maars.  The southernmost of the two summit crater lakes, Botos, is cold and  clear and last erupted about 7500 years ago. The more prominent  geothermally heated northern lake, Laguna Caliente, is one of the  world's most acidic natural lakes, with a pH of near zero. It has been  the site of frequent phreatic and phreatomagmatic eruptions since the first historical eruption was reported in  1828. Poás eruptions often include geyser-like ejections of crater-lake water. (Global Volcanism Program)  Poas Location: 10.20° N, 84.23° W Elevation: 2.708 m Photo: Rolf Cosar Photo: Rolf Cosar HOME