The Cerro Chato, also known as the Chato Volcano is a dormant volcano that first erupted 38,000 years ago and last erupted 3,500 years ago. One of its eruptions paved the way for the nearby La Fortuna Waterfall. Cerro Chato has two peaks, Chatito (little Chato) and Espina (Thorn), as well as a 1,640-ft (500-m) crater filled with green water. At an elevation of , Cerro Chato stands much shorter than its neighbor Volcano Arenal, but this also makes it hike-able. Classified as a difficult hike and at times a climb, it is recommended only for hikers of good physical condition. The average hike lasts 5 hours, and can be very muddy when it rains. Due to certain minerals in the water, some advise no swimming, however most locals disagree and swim in it regardless.