The 'Gruta do
Carvão' lies beneath the streets and buildings of Ponta Delgada.
There is another cave with a similar name, called Algar do
Carvão on Terceira. The explanation is easy, Carvão
means 'coal' in English, and refers to the black colour of the cave
walls. Most of the caves on the islands are lava tubes, and lava very
often has this dark black colour. As a result there are various "Coal
Pits". Of course there is no coal found on this islands.
This cave is said to be the longest cave on São Miguel. The
length is given with 1,650m, which is a bit strange. In ancient times
the cave was reported to be five kilometers long, which obviously was a
bad estimation. Today there are three parts of the same lava tube,
which are not connected any more. All three parts together have a
length of 1,650m.
The entrance is behind a factory, a flight of stairs - lit by a string
of light bulbs - leads to a roomy passage. The passage ends where a
large stormwater drain broke into the cave ceiling. 'Gruta do
Carvão' has extraordinary multi-coloured rock formations with
weird shapes. They are the result of lava remains cooling down in the
tube.
We love cats. 
