The Northern Lowlands' Arenal Volcano gets all the press, but we nominate Poás, in the far northern Central Valley, as Costa Rica's coolest volcano experience. Arenal requires you to view it from afar, while Poás lets you peer right inside what is thought to be the largest active volcanic crater in the world. The ride up here is disarming: pleasant farms and lush green cloud forest line the volcano's slopes. Friendly fruit and jam vendors along the road beckon you to stop and sample their wares. Only when you get to the bubbling, gurgling, smoking summit do you leave that pastoral scene behind and stare into the crater.
The park is nearly always open, but officials monitor activity closely and close access to Poás's 2,708-meter (8,885-foot) summit at the slightest hint of anything irregular. Volcanic activity has increased, but remained at a steady level here since a series of eruptions in 2006. For your own health and well-being, step away for fresh air at least once every 10 minutes, lest you be overcome by the sulfur fumes. A good place to take that break is the park's bustling visitor center. With complete park information, a cafeteria, and a gift shop, it is one of the country's best.
From Alajuela, drive north through town and follow signs, Volcán Poás National Park, Costa Rica
/2482–2424; /192-national parks hotline in Costa Rica