Caves Tour (Algar Do Carvão, Gruta Do Natal, Furnas Do Enxofre) from Azores

The Algar do Carvão is classified as a Natural Monument and is located inside the Guilherme Moniz caldera, at a height of 640m, about 12 km away from the city of Angra do Heroísmo.

It is a remarkable volcanic cavity whose geological and speleological importance has been rightly pointed out by several national and foreign specialists.

After a trachytic eruption originated long before, a new eruption, this time basaltic, tore the preexisting lava flow and began a process that would lead to the formation of a strombolian volcano, consisting of two cones, in its upper part composed of slags, which had a very rich effusive phase, of very fluid lavas.

Inside it is possible to observe the domes created by the attempts to exit the lava, as well as some basaltic "covers" that still resist clinging to the primitive rock. Due to the action of water on the interior ceilings of this remarkable empty volcanic chimney, it is possible to observe ferrous and siliceous deposits.

The presence of silica stalactites is, in particular, the one that most catches the attention of visitors and further raises their curiosity. It is possible to appreciate still other formations originated during the formation of the Algar. In the basal part ends in a small pond, which brings an additional beauty to the cave.

The beauty of this Algar also passes through the vegetal communities that cover the interior of the volcanic chimney, being possible to observe different birds that seek refuge. The diverse species of plants, molds, arthropods and other groups are also an important patrimony of this algar. The first descent into the interior dates from 1893. Only in 1966 was the public access tunnel opened.