San Giovanni cave is located in the municipality of Domusnovas, in the province of South Sardinia, Sardinia.
The cave has been recognized as a natural monument, established pursuant to Regional Law no. 31/1989 with determination D.G. no. 2777/1999 of the Department of Environmental Defense of the Autonomous Region of Sardinia, and as such subject to restriction.
Now closed to traffic, it was the only one in Italy, third in the world (after France and Australia) to be passable by car. It is reached by exiting the town of Domusnovas in a northerly direction and taking the provincial road that runs alongside the San Giovanni river.
It is a destination for sport climbers from all over Europe due to the spectacular rock walls located in the municipal territory.
Exiting the town, the asphalt road leads to the foot of the mountain and to the south entrance. This entrance suddenly appears before the visitor's eyes, in all its grandeur.
The cave is overlooked to the east by Mount Acqua (540 m) and to the west by Peak San Michele (908 m).
The cave is a fine example of a karst phenomenon. The karst phenomenon that generated it is due to the flow of an underground river that caused the collapse of a rocky limestone mass.
Perd'e Cerbu massif near the cave.
The main branch (road level), 850 meters long, opens with another monumental entrance into the Oridda valley. The main branch, entirely crossed by the river that collects the waters of the valleys upstream, is characterized by large halls, large pool-like concretions, the largest of these concretions is located near the north exit, and by stalactites and stalagmites. In addition to the main branch, the cave extends over two other levels, (accessible only to experts), making the cave 2000 meters long:
The upper or fossil branch called "Ramo Bobore";
The active branch called "Su stampu de Pireddu". The active branch is the most interesting, as it consists of a series of tunnels and passages for a total length of 2 km, and with the presence of underground lakes and siphons. This branch is still being studied today.
Source: https://it.wikipedia.org/wiki/Grotta_di_San_Giovanni
