Visited in the 19th century by Prince Alberto of Monaco and the naturalists Fouqué and Hartung. In 1879 whilst on a oceanological expedition to the Azores, Prince Alberto visited this cave. He was lowered down the entrance shaft on a rope.
The cave consists of a perfectly arched passage about 40 m high and 194 m long. This is a typical lava cave, formed by the molten lava draining out of a cooling mass. The best time to visit the cave is between 11.00 and 14.00 when the sun shines through the narrow funnel like entrance and lights up the interior with its abundant plant life. In the 20th century a staircase enclosed within a 37 m high tower was built inside the cave, providing easy access for the athletic visitor. At the base of the stairway is a lake of warm sulphurous water called the Furna do Enxofre from which the cave takes its name.
Text by Tony Oldham (2002). With kind permission.