The Sierra Utrera constitutes one of but a few solitary places with its own special environment on the Costa del Sol and is actually located in the municipality of Casares but like the Hedionda Roman Baths is closer to the town of Manilva than Casares, and features the spectacular gorge known locally as the´Canuto de la Utrera´.

Sierra Utrera's striking landscape is a result of erosion of the limestone ridge which runs from just behind Manilva across to the top of the Hedionda Valley. The Jurassic age limestone is about 150 million years old and was laid down in a marine corridor that extended from the Gulf of Cádiz to Alicante between the present Atlantic Ocean and Mediterranean Sea. These seabeds were uplifted to an elevation of over 1300 meters during the Tertiary era, resulting in a modest mountain range of flat-lying limestone, which is rare in Andalucia. Later, a series of fractures, cracks and faults at right-angles  were exploited by erosion and produced the alleys between large blocks of limestone visible today. The blocks themselves have been subjected to both dissolution by water and freeze-thaw splitting action which, working on the limestone’s horizontal beds, resulted in the various shapes visible today.

This type of geololigal formation is known as ‘Karst’, taking its name from a region of the Adriatic coast spanning Slovenia and Croatio, where this feature was first studied.

It has characteristics similar to the Torcal de Antequera, but with a series of gorges called ´canutos´. This type of formation does not appear  in the Torcal de Antequera and is also the most southerly of the torcals in  Europe.

Inside there are many galleries and underground rivers, more than one hundred known caves between the shelters, wells and summits, giving ample range for potholing activities and a  500 hectare surface of high biological, geologic, historical and geophysical value.  The natural qualities of the place are concentrated in distinct ecosystems which are practically unique in Europe, especially where flora and fauna is concerned. There are many important species of  animals to be seen including Bonelli´s Eagle, the egyptian vulture and the otter, among many others.

On an archeological level, there has been a constant human presence sinc e the Palaeolithic age and settlements since Neolithic times right through distinct historic times including the Iberians, Phoenicians, Romans, Moors up to the present day.