The island Corsica is one of the 26 régions of France. It is separated from the continental mainland by the Ligurian Sea, but it is considered a part of Metropolitan (or continental) France. Corsica is famous for being the birthplace of Napoleon Bonaparte.
The very mountainous island has a Mediterranean climate: hot, dry summers and mild, rainy winters. The natural vegetation is called macchia, a composition of almost impregnable Mediterranean forests, woodlands, and shrubs. There are many mountain trails and climbing tours, but it is almost impossible to cross the island without a trail.
The geology of the island is a central mass of granite which forms the backbone of the island, surrounded by metamorphic rocks. 250 million years ago this granite was formed by the up-rise of magma from the upper mantle. 50 million years ago with the formation of the Alps, the island was affected by the same forces. A mass of sedimentary rock, thrust against the eastern side of the island, was transformed into metamorphic schist. The mountainous relief is a result of erosion and glaciation. The abundant precipitation causes intensive erosion, which formed steep sided, V-shaped valleys all around the island.
There are 110 caves in Corsica, mostly in Haute Corse. The most important caving area is the Oletta massif with 16 caves. The Ghisoni Cave with a depth of 117 meters is the deepest. There are two caving clubs, the I Topi Pinnuti (Corsican for bats) in Bastia and the L'Association Cortenaise de Spéleologie in Corte. There is also cave rescue group called Spéleo Secours de Haute Corse.
The crystalline and metamorphic rocks of Corsica are not soluble, and so there are almost no karst caves. Most of the caves are of tectonic origin, formed by the collapse of steep valley sides. There are almost no underground sites of touristic interest.