At the time, it destroyed 1,500 hectares, affected 32,000 hectares and covered over 800 hectares with lava, as a result of its emissions of pyroclasts, ash, steam and burning clouds.  There is no record of any eruptions that took place during the Spanish Conquest and subsequent colonization, but some carbon-dated potsherds and samples of coal suggest there was volcanic activity between 1200-1500.

The episode of 1968 began with an eruption on 29^th-30th July, killing 87 people and causing some damage.  A quiet phase followed from 31^st July-9^th August, during which time the volcano emitted hot vapors and large amount of ash.  On 9^th August, fumarolic activity began in the new crates, on the 14^th explosions were heard, and on the 19^th there was a lava flow 25 meters thick that advanced towards the Tabacón River Valley at a rate of 10-30 meters a day.  Today, parts of the altered slopes have been carpeted by vegetation, and others are just beginning a stage of natural colonization in an excessively humid and cloudy habitat.

The road between La Fortuna and Arenal Lagoon (15 kms) leads to the very foot of the volcano on its western flank.  The view includes the fiery glow of the volcano at night, the majestic rim and the surrounding lakes.  The region of lakes, volcanoes, mountains and hot-water rivers can be reached from the Central Valley by the road between San Ramón and La Fortuna (67 kms).