Until the early 1990s, the cave was the only accessible road for cars traveling between Domusnovas and the mines of the Oridda valley.
The cave is formed from limestone dating back to the Cambrian period, making it one of the oldest geological formations in Italy.
The massive arched entrance reaches a height of nearly 60 meters.
The site was historically used as a shelter by local populations during periods of conflict.
It is home to specialized cave-dwelling fauna, including rare species of subterranean crustaceans.
The internal temperature remains constant at approximately 15-16 degrees Celsius throughout the year.
Grotte di S. Giovanni is a massive natural tunnel cave located in the limestone massif of Monte San Giovanni in southwestern Sardinia. It is one of the few natural caves in the world that served as a public road for vehicular traffic until the 1990s. The tunnel spans approximately 850 meters in length and cuts entirely through the mountain, connecting two sides of the valley. The cave features a riverbed that runs along the bottom, which has been dry for centuries due to tectonic shifts. Visitors can observe distinct karstic phenomena, including stalactites, stalagmites, and ancient flowstone formations. The cave's entrance is marked by a ruined medieval chapel dedicated to Saint John the Baptist. It is managed by a local cooperative that provides guided tours through the illuminated trail.
The massive, naturally arched entrance provides a dramatic framing effect when looking from the exterior toward the sunlight.
Wear sturdy, non-slip footwear as the path can be damp and uneven.
Bring a light jacket even in summer, as the internal temperature is significantly cooler than the outside.
Confirm tour availability with the local cooperative before traveling, as access is restricted to guided groups.
Attempting to explore the cave alone or without a guide, as the site is strictly regulated for safety and conservation.
Tours are seasonal and subject to change based on weather conditions and group bookings; typically closed on Mondays.
Do not touch the rock formations or stalactites to prevent damaging centuries of mineral deposits.
