The Arenal Volcano (Spanish: Volcán Arenal) is an active andesitic stratovolcano in north-western Costa Rica (10.5N, 84.7E), about 90 km north-west of San José, in the province of Alajuela. Once locally known as Mount Arenal (Cerro Arenal), Arenal was presumed extinct until July 29, 1968 when it erupted after approximately 400 years of dormancy. The eruption wiped out the town of Tabacon and killed 87 people [cite: http://www.arenal.net/arenal-volcano-1968-eruption.htm]. It has been in continuous eruption since then.
Arenal rises 1657 metres above sea level and overlooks Lake Arenal; both are part of Arenal National Park. The country’s most active volcano, Arenal’s eruptions are strombolian in type, being frequent but moderate. This constant activity makes Arenal a popular tourist destination, especially at night (See image). The last major eruption of Arenal occurred on August 23, 2000. Most of the time, the volcano is surrounded by clouds near the tip, and it is touted as good luck to see the whole volcano without clouds. The volcano heats several hot springs nearby, including Tabacon, a popular tourist destination.