The Algar do Carvão – a national reserve on the island of Terceira (Azores) – belongs to the caldera of one of the four volcanos of the island. It is a 45 meter deep volcanic vent located at about 600 meter above sea level and about 2’000 years of age. The picture shows the view upwards from the inside.
As rainwater falls into the vent, a lot of plants grow on the upper part. Further down the walls are dark like coal – in Portugese: carvão.
Looking donwards, there is a little rainwater pool …
structures & shapes 