1. From Angra: 3-Hour Volcano Tour
Discover the volcanos and volcanic caves of Terceira Island on this geology lover's guided tour. Visit Algar do Carvão, Furnas do Enxofre and Gruta do Natal with an expert guide. Meet your guide and driver for pick-up at your hotel and head to the first stop on the tour — the inactive Algar do Carvão. Visit it from the inside and discover its small lake and fascinating geological formations. Next head to Furnas do Enxofre, a small strip of land with 20 fumaroles expelling white vapor into the air. You'll also see native flora like the Azores juniper and the Azores blueberry. Top off your tour with a visit to Gruta do Natal (Christmas Cave), a system of caves known as a lava tube, full of spectacular volcanic formations.