Grotta Gigante: one hall 98.5 m high, 1,000 steps

The Grotta Gigante, at Sgonico on the Karst plateau outside Trieste, is a single cave hall 98.5¹ meters high, 167.6¹ long and 76.3¹ wide, visited on 500¹ steps down and 500¹ back up at a constant 52°F (11°C), for €15.

One hall, 98.5 by 167.6 by 76.3 meters

The cave is one chamber, 98.5¹ meters high, 167.6¹ meters long and 76.3¹ meters wide, and it has been in Guinness World Records since 1995 as the largest natural hall in the world open to tourists.

The hall also holds the longest geodetic pendulums in the world, run by the University of Trieste, which makes it a working research site as well as a show cave.

One caveat on the numbers: the dimensions and the record come from an encyclopedic source, because the operator's open pages don't display them. The prices, the steps and the temperature below are the operator's.

500 steps down, 500 up, at 11°C

The tourist route is 850¹ meters long and goes down 101¹ meters, on 500¹ steps into the hall and 500¹ back out. It takes about an hour, at a constant 11°C, which is 52°F in any month.

That is the physical fact to plan around. A thousand steps in an hour is a workout for knees, and the second 500¹ are all uphill. Bring a layer even in August, and shoes with grip.

Booking is required. The operator's timetable of departures is not in our records, so check it when you book.

€15, €12, €8, and the FVG Card

The full ticket is €15, reduced €12, ages 6 to 18 pay €8, and children up to 5 go free. Groups of 15 pay €12 each and school groups €6.

The FVG Card, the regional visitor card, gives free entry together with one child under 12. If you're touring Friuli with a family, that single line can be worth more than the card's other benefits.

The Opicina tram, back since July 27, 2026

Line 2, the Opicina tram, climbs 5.175² kilometers from central Trieste onto the Karst, and about 800² meters of that is pushed by a funicular up gradients of 26%, a system with no equal in Europe.

It resumed on July 27, 2026, with a provisional terminus in Piazza Dalmazia. The historic terminus in Piazza Oberdan is due for works from late 2026 to June 2027.

Its recent record explains the caution. The line stopped after an accident on August 16, 2016, came back on February 1, 2025, stopped again on October 12, 2025 with a cable fault, and returned in July 2026. The official transport page had not recorded the 2025 stoppage when checked, so the return comes from a news agency.

On board, loads are capped at 80% of capacity and standing is allowed only on the rear platform. It is not accessible to wheelchair users. Urban Trieste tickets are valid, and you can pay contactless on board.

The tram takes you onto the Karst. The last stretch from the line to the cave at Sgonico is not covered in our records. The city below is at Trieste, and why its history runs differently from the rest of Italy at Trieste was not Italian.

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