Arenal National Park Located in northwest Costa Rica, Arenal suddenly became active in 1968 when 78 people were killed and two villages were destroyed. The volcano is still active, producing daily streams of hot, red lava and huge ash columns. The degree of activity varies from week to week. The best place to view the volcano is at the base of the mountain. Located at the base of the mountains are the Tabacon Hot Springs, which include a waterfall, several swimming pools, smaller pools, a swim-up bar, and a slide. Because of the strong winds, some rate the surrounding Lake Arenal as one of the best windsurfing spots anywhere. It lies west of the volcano with hotels and fishing nearby.