Grotta Gigante, on the Carso plateau above Trieste, contains the largest tourist show cave hall in the world, a single chamber deep enough to fit St Peter’s Basilica inside with room to spare, and it holds 4.8 on Google across more than 9,000 reviews.
Visits are guided only, descending 500 steps to a chamber a hundred metres underground at a constant eleven degrees; the guided tour and museum entry ticket sold through GetYourGuide carries the same 4.8 rating across 69 verified bookings.
Local tip: Bring a light jacket even in summer; the temperature underground doesn’t change with the seasons.
Good to know
- Where: Borgo Grotta Gigante, 42/A, 34010 Sgonico TS, Italy
- City: Trieste area
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