While the Mediterranean sea is vast and impressive, the most important cave diving site is in the north west of Sardinia, close to Porto Conte bay, Alghero territory. Thanks to the huge limestone cliffs of Capo Caccia and Punta Giglio, there can be found more than 300 caves above and below water, with about 30 large (and many small) underwater sea caves. The Nereo Cave is considered the most important, and also the largest in the Mediterranean Sea. One of the east side of Sardinia, there are many underwater rivers which reach the sea by different, lengthy routes. Here one of the deepest fresh water caves exits at more than 110 m (360 ft) depth. Cala Golone is a departure point for cave diving in Sardinia's largest cave systems which are usually reached by sea. Bue Marino is the longest known, and there are several others with various lengths and depths.