Grotta Gigante

The entrance to Grotta Gigante lies in a suburb of Trieste, Borgo Grotta Gigante.

Useful Information

Location: In the village Borgo Grotta Gigante, North of Trieste.
(45°42'34.77"N, 13°45'53.27"E)
Open: APR to JUN Tue-Sun, Hol 9-17.
JUL to AUG daily 9-17.
SEP Tue-Sun 9-17.
OCT to MAR Tue-Sun, Hol 10-16.
Tours on the full hour.
Closed 01-JAN, 25-DEC.
Fee: Adults EUR 13, Children (6-18) EUR 8, Children (0-5) free, Seniors (65+) EUR 10, Students EUR 10, CAI EUR 10, SSI EUR 10.
Groups (15+): Adults EUR 10, Schools EUR 5.
Classification: SpeleologyKarst cave
Light: LightIncandescent Electric Light System
Dimension: H=107 m, L=280 m, W=65 m, T=12 °C.
Guided tours: D=45min V=85,000/a [2000] V=64,200/a [2008]
Photography: Photographs are allowed with or without flash, except in the first part of the descent for safety reasons (risk of slipping).
Accessibility: definitely not
Address: Grotta Gigante, Borgo Grotta Gigante 42a, 34010 Sgonico, (Trieste), Tel: +39-040-327312, Fax: +39-040-327312. E-mail:
Società Alpina delle Giulie di Trieste, Commissione Grotte "Eugenio Boegan", Via Donota 2, 34100 Trieste, Tel: +39-040-630464, Fax: +39-040-368550, e-mail contact.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


1840 first exploration of the cave by Antonio Federico Lindner.
1890 second entrance near todays Museo di Speleologia discovered and explorations increased.
1904 start of development as a show cave by the Club dei Touristi Triestini.
05-JUL-1908 opened to the public, lighted by 4000 candles.
1957 electric light installed.
1995 included into the Guiness' Book of World Records.
1996 new paths built, separate exit.


main chamber.

Grotta Gigante is a really huge single cavern, 280 m long, 65 m wide and 107 m high. This was long time the biggest chamber of any show cave in the world. However, if you interpret La Verna in France a show cave, it is the new number one. Some other passages exist, but are not part of the tour. The cave is part of the system of the underground river Timavo, which enters the karst in ShowcaveŠkocjanske Jame, nearby in Slovenia.

A seismograph, the longest geodetical pendula in the world, and other instruments for the measurement of the land tide are in function within the cave. Land tide is the extremely small movement of the Earths crust, because of the gravity of the moon. It is caused by the same mechanism as water tide, but the impact on solid matter is much smaller and therefore much harder to detect. One very important reason for this location was the constant temperature of 12 °C, another was the height of the cavern. The instrument consist mainly of a 100 m high pendulum.

The cave has very large stalagmites, with a special look. They are called Speleothempalm trunk stalagmites or plate stack stalagmite because of their characteristic form. The palm trunk stalagmite is typical for a big chambers close to the surface.

Because of the extraordinary high ceiling, the falling water drops get very fast. When they hit the ground, the high energy of the drip makes it burst into a spray of water. The area the spray covers depends on the size of the original drop which depends on the amount of water from the surface. So the diameter of the stalagmite varies very much with the climatic changes outside the cave. Every plate of the stack represents a period of sufficient water.

Near the entrance of the cave is a Museum of Speleology with geological, speleological and archaeological exhibits. It was completely refurbished some years ago and is now accessible without cave ticket. So if you are in the area and the cave tour is too much sport, have at least a look at the very interesting exhibition.

Grotta Gigante Gallery