Many cavities and caves may be observed along the routes that cross the Alta Murgia. The karstic nature of the local geology (the deep erosion of calcareous rock by rainwater) has favoured the creation of an extensive system of caves and grottoes. The association of speleologists of Puglia lists around 550 formations in the province of Bari alone. The underground caves take many different and fantastic forms and they give the area its unique charm. Amongst these many formations, the ‘Grova della Cavallerizza’ comprises both natural phenomena and some massive quarried blocks. It is formed by three potholes, from eight to eleven metres in diameter and blocks of stratified rocks. The holes are interconnected by narrow passages and at the base of the largest pothole lie mounds of rocks that have fallen into it and through which rainwater flows in bad weather.
Grava della Cavallerizza, agro di Ruvo di Puglia (Fonte internet )