Spectacular strombolian eruptions such as reflected here in Lake Arenal on June 15, 1997 draw many visitors to Arenal, the youngest stratovolcano in Costa Rica and one of its most active. The oldest known Arenal products are only about 7000 years old, and the volcano was active for several thousand years contemporaneously with the older Chato volcano (lower right). Arenal's most recent eruptive period began with a major explosive event in 1968, and frequent explosive activity and slow lava effusion have continued into the 21st century. Photo by Olger Aragón, 1997.