Poás volcano is a powerful symbol of the geothermal forces that formed Costa Rica. When the mist and clouds part you’ll see the sulfuric, bubbling, green rain fed lake at the bottom, surrounded by smoke and steam rising from fumaroles. Water from the lake is constantly seeping through cracks in the hot rock, evaporating and building pockets of steam.
When the pressure in these pockets exceeds the weight of the water above, the steam breaks through in geysers that rocket up to 820 feet (250 meters) high. Don’t worry about getting a shower though, the crater is 1,050 feet (320 meters) deep. At almost a mile (1.6 km) across it’s also the largest active crater in the world. New safety features have been added to protect visitors in case of particularly heavy activity.
