Algar do Carvao is on Terceira island. It is a ancient lava tube in which we enter through a small tunnel under the visitors center. Entering the tube, you can look up to the vent 45 meter higher and see the sky. The tube to the vent is covered with a green forest made of several species of moss and fern, some endemic to the Azores. It is inhabited by endemic beetles and spider.

After the entrance, a serie of steps are going done the cone, and the forest gives way to black volcanic walls, with silica deposits forming white stalagmites and stalagtites. At the end of the cave is a 15 meter deep crystal lake.

Algar do Carvao can be reach by car or taxi from Terceira airport or from Angro do Herosimo (20 minutes). It is open in the afternoon with a fee.

Altogether, I enjoyed Algar do Carvao even though I am not a big fan of caves. I am skeptical about OUV however.