Algar do Carvão is a stunning volcanic chimney located on Terceira Island in the Azores, Portugal. This remarkable geological formation was created over 3,200 years ago by a volcanic eruption and offers a unique opportunity to explore the interior of a volcano. Visitors can descend 90 meters into the cave, where they are greeted by impressive stalactites and stalagmites, as well as dark basaltic walls. Unlike most caves, Algar do Carvão is open to the sky, adding to its mystical atmosphere. The cave is a popular destination for those interested in geology and volcanic landscapes, and guided tours provide insights into its fascinating history.