Geology in the Sierra de Grazalema Natural Park
The rugged landscape and deep valleys are a classic consequence of a karstic geology that offers spectacular landscapes rich in escarpments, caves and gorges, all of which are a result of the erosion of limestone by the action of water over millions of years.
Water erosion has created stunning canyons, the best known of which is the Garganta Verde (“Green Gorge”), with a 400 metre deep drop from top to bottom, and ideal for canyoning. It is also home to a subterranean labyrinth of caves and grottos, the most outstanding of which is the Cueva de Hundidero-Gato. This is Andalusia's longest cave, and is the hibernation site for some 100,000 bats, the largest colony in Spain.