Rising over a mile in height, Arenal Volcano in the northwestern region of Costa Rica offers visitors a rare opportunity to view one of the world's most active volcanoes. After sleeping quietly for over 400 years, Arenal erupted with tremendous force during July 29-31, 1968. "A lunar landscape" was created by the volcano as several square miles were covered by rocks, lava and ash. Over twenty years later Arenal continues to erupt, but at a smaller scale. Visitors viewing the volcano can see it throw out red hot rocks up to 1000 feet in height and some of the rocks are over 25 feet in diameter! In addition, the volcano can be fairly noisy with explosions which sound like dynamite that echo off the nearby mountains.

At night lava flows and the ejection of glowing hot rocks can provide viewers with an impressive fireworks display. Short periods of inactivity are usually followed by loud explosions, large "cauliflower" shaped eruption clouds, and the emission of hot, red rocks which crash and shatter down the steep gray slopes of the volcanic cone and can be heard from a mile away.