Saint Michael's Cave is a series, or network of caves made of limestone, which are found on the Rock of Gibraltar. St Michaels Cave is located on what is called the Upper Rock, inside the Upper Rock Nature Reserve of Gibraltar.
The cave was created by the slow seepage of rainwater through the rock, which turned into a carbonic acid solution that actually dissolved the rocks of the cave. The process made the tiny cracks of the geological faults of Gibraltar grow into very long passages and deep caverns over the thousands of years of its formation. The Cathedral Cave, part of St Michaels cave was at one time thought to be bottomless, and was long spoken of in the legends of Gibraltar.
The Rock of Gibraltar has long been considered to be one of the pillars of Hercules, and this too adds to the mystique and legend, and since it hosted the cave, the caverns themselves were thought to be the Gates to Hades, or Hell, an entryway to the Underworld where the dead rested.
In the latter part of 1974, proof that the cave was known to and used by prehistoric men was made clear with the finding of art on the cave walls, showing an ibex drawn there that was traced to the Solutrean period (dating the cave art to about 15-20 thousand years ago), but later, two Neanderthal skulls that were found in Gibraltar tell us that this cave could have been discovered and used as early as 40,000 BC.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.