Fodor's Expert Review Volcán Sierra Negra

The island's signature excursion is a guided 9-km (5½-mile) trek ascending the 1,370-meter (4,488-foot) Volcán Sierra Negra. The volcano's crater—roughly 10 km (6 miles) in diameter—is the second-largest in the world. The volcano erupted in October 2005, but, thankfully, the event threatened none of the island's population, human or animal. Seismologists keep close watch on any untoward activity and will suspend excursions if needed.