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4. Domusnovas – San Giovanni Cave

The San Giovanni Cave in Domusnovas is a masterpiece of nature, carved by water over 6 million years through Cambrian rocks dating back 530 million years. Stretching 860 metres, it holds a Western world record as the longest natural underground road tunnel.

Strategically located within the Iglesiente 'Metalliferous Ring', the cave was a vital infrastructure for over 30 mining sites, including Sa Duchessa and Barraxiutta. This unique transit route transformed a natural wonder into a commercial artery for transporting zinc, silver-lead, and timber. To optimize transport compared to the longer external 'decauville' routes, a toll system based on cargo weight was implemented for carts and later motor vehicles.

Since its 1999 designation as a Natural Monument by the Sardinia Region, the cave has been closed to traffic. This has allowed a vital biological regeneration, restoring its natural concretion processes. Today, visitors can explore a unique environment where industrial heritage meets geological evolution, making it an essential destination for understanding how mining needs shaped this spectacular natural transit cave.

Superlatives:

Longest natural underground road tunnel in the Western world (860m). A unique global example of a 'transit cave' carved in 530-million-year-old Cambrian rocks, featuring a historical mining toll system.

Useful information:

Opening days and hours: Open all day, every day. Hours vary by season: Low Season (Oct-Mar): Mon-Fri, 10:00 – 17:00. Mid Season (Apr-May): Daily, 09:00 – 18:00. High Season (Jun-Sept): Daily, 09:00 – 19:00

Recommended visit duration: 90 minutes

Disabled access: for details see website

Facilities for children: yes

Picnic area: yes

Gift shop: yes

Email: consorzionaturaviva@gmail.com

Phone: +39 348 0553309

Website: www.grottasangiovanni.com

Address: Località “San Giovanni” s.n.c., 09015 Domusnovas

Geolocation: 39.336774797268184, 8.627536974120352