Lake Arenal

Another location which is far more mysterious in origin can be found near the shores of Lake Arenal. Known for the majestic volcano that stands sentinel over the valley, Arenal became the focus of one Payson Sheets, an archeologist from the University of Colorado. Using NASA remote sensing technology, Sheets discovered the existence of remote footpaths both around and under the current Lake Arenal during these aerial surveys in 1985.
These footpaths, some dating back to 500 B.C., lifted a curtain on the life and culture of the ancients who used them as part of their daily existence. Sheets and other behavioral archeologists theorized that wandering bands may have lived around the volcano as early as 10,000 B.C. although a permanent settlement probably did not become established until around 2000 B.C.
These early settlers would move away during eruptions and then return to their crops and settlement when Arenal grew quiet. Much like the citizens of Guayabo, these lake residents vanished around 1400 B.C. The belief is that a plague, not the Volcano, is what ended their days.