Jungle-covered lava flows
Since its last eruption decades ago, Arenal Volcano has been slowly and steadily reclaimed by the jungle, creating a trail system of dark volcanic gravel and huge boulders of frozen lava. The volcano itself is a bit of a phantom, rarely emerging completely from its veil of clouds. But depending on the time of year--and with some luck--you may get a perfect postcard shot.
But even without a visible volcano, the area surrounding the National Park and the town of La Fortuna is still a hotspot of wildlife and accessible trails. The cooler weather also helps the transition into Tropical Climate, making Arenal a popular first stop on any trip.