Algar do Carvão

Coal Pit - Gruta do Carvão

Useful Information

Location: At the Terra Brava, center of Terceira island.
Open: OCT to MAY Tue-Sun, Hol 14:30, 15:30, 16:30.
JUN to SEP Tue-Sun, Hol 10:30, 11:30, 14:30, 15:30, 16:30.
Fee: Adults EUR 5, Reduced EUR 4. [2014]
Classification: Speleologylava tube
Light: LightIncandescent Electric Light System
Dimension: L=100 m, VR=90 m.
Guided tours: D=30 min, V=22,000/a [2009].
Address: Os Montanheiros, Rua da Rocha 8, 9700-169 Angra do Heroísmo, Tel: +351-295-212992, Cell: +351-961-362215, Fax: +351-295-216465. E-mail: contact
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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1893 discovered.
1963 exploration completed.
1968 opened as a show cave.
2004 cave entrance building and interior renovated by the mountaineering club Os Montanheiros.


Algar do Carvão is a huge, about 100 m long lava tube, which is the remains of a some 2148+/-115 year old volcanic eruption of the nearby Terra Brava (707 m asl) named do Pico Alto. The cave is the now empty tunnel of a lava flow. The name means coal pit in English, and was given to the cave because of the cave walls of dark black lava. Of course there is no coal found on this islands.

Very astonishing is the fact, that this volcanic cave contains stalactites and stalagmites. They were formed by silica, dissolved from the lava, not by calcite as in karst caves. This is really exceptional, and the result of a special chemistry of the lava.

The cave is entered by going down stairs inside a shaft, a former vent of the lava flow. The end of the tour is a subterranean lake, formed by rain water. Depending on the season and the amount of rain water, the lake can be up to 15 m deep. The whole cave is spacious, the passage is up to 45 m in diameter.

The cave and the surrounding area was declared a natural monument after the initiative of the mountaineering club Os Montanheiros.

Close to the cave are the Furnas do Enxofre, sulfuric springs, well worth a visit. The best time for a visit is early in the morning, as the area gets very hot when the sun shines on the black rocks.

At the cave starts a trail which goes around the Terra Brava. It is said to be probably the most beautiful walk on Terceira. But be careful with bulls, which are bred for bullfights. The walk takes four hours.