Just north of Monteverde lies one of Costa Rica's defining sights - Volcan Arenal. Arenal, part of the Ring of Fire, is considered one of the planet's most active volcanoes, continuously oozing a slow effusion of lava down the southeastern part of the slope that's incredible to view at night, and occaisionally belching a cloud of gas, rock and ash hundreds of feet into the air.

 

Accomodations around Arenal are plentiful, very scenic, beautifully manicured, and range from the more economical all the way to very pricey, all-inclusive luxury hotels. Arenal is considered a prime spot for a vacation home. Because of the volcano's near constant activity, hot springs are plentiful at resorts all around Arenal. Spas that offer gourmet cuisine, yoga, massage, and hot pools of differening types with varying mineral concentrations are very successful in the area. Night viewing of the volcano while lingering in a hot spring under the stars, sipping cocktails is a unique and unforgettable experience. Adventure tourists pack the surrounding towns during an eruption, so much so that the goverment must make a special effort to maintain safety and order when Arenal erupts.

Just to the west of Arenal lies Lake Arenal, a natural lake that was enlarged to create Costa Rica's largest hydro-electic power project. Lake Arenal is picturesque, perfect for windsurfing and fishing, both of which are popular activities at the lake.

 

At roughly 7:30 a.m. on Monday July 29, 1968 – after having lain relatively dormant for over 400 years – Arenal Volcano erupted with violence and fury.  Extreme eruptions and volcanic activity continued for several days, killing some 87 people and burying over 15 square kilometers in rock, lava and ash.  The eruptions affected a total of over 232 square kilometers in the surrounding area to varying degrees, with damage to crops, property, livestock and forests.

At the height of its activity this La Fortuna volcano was spewing out massive amounts of lava and ash and tossing giant rocks for distances of up to a mile at speeds of some 600 meters per second.

The explosions formed three new active craters.

Since that time, Arenal Volcano has maintained nearly constant activity ranging from soundless explosions with large mushroom-shaped clouds of ash overhead to booming explosions sending hot rocks nearly a kilometer into the air to pyroclastic explosions highlighted by rushing gases and flowing  lava pouring down the side of the volcano.  For visitors to Costa Rica, volcano viewing is the most promising at Arenal – no other volcano has been this consistently active.

Arenal Volcano rises to approximately 1633 meters at its summit, although the exact summit height changes frequently due to the volcanic activity.

 

Prior to the 1968 eruption, Arenal Volcano was a nearly perfect cone-shaped, rainforest blanketed volcanic mountain with minor fumarole activity.  Local residents had named it variously: Arenal Peak, Pan de Azúcar (Sugarloaf), Canasta Volcano, and Río Frío Volcano.

The area around Arenal Volcano has been home to indigenous populations for thousands of years.  Over this time, these residents have weathered scores of periods of intense volcanic activity.

In Costa Rica, volcanoes are a natural part of the landscape, contributing to the area’s history and folklore, The Guatuso Indians, for example, believed the volcano was home to the God of Fire.

In geological terms, the Arenal Volcano is relatively young, only some 4000 years old.  Prior to the 1968 eruption, the volcano’s last major eruption has been dated at around 1500 AD and lava flows from this period have been tentatively identified.