Fodor's Expert Review Algar do Carvão

Climb deep inside an extinct volcano at this 1,804-foot volcanic cave located toward the middle of Terceira. You’ll be guided 148 feet down a set of stairs to the floor of the cavern before descending another 115 feet to a crystal clear lake fed by rainwater (which completely disappears during dry summers). Though the stairs are on the steep side, they have handrails and are not challenging to descend or ascend—just be sure to dress warmly, as the cave becomes colder and wetter the farther down you go. Along the way you’ll see unique stalactites and stalagmites. Opening times vary depending on the season, but are generally limited to a few hours in the afternoons, so check before you go.