The exceptionally large size of the main underground chamber of the Grotta Gigante, situated near Borgo Grotta Gigante, in the municipality of Sgonico (Trieste), enabled it to enter the Guinness Book of Records as the world’s largest show cave in 1995.
The cave can be accessed by a downhill tunnel; the flights of steps lead down to the main chamber, which is 98,50 metres high, 76,30 metres wide and 167,60 metres long (total volume 365.000 m3): the cave is crossed by a geodetic pendulum for the study of earth tides. The floor and the ceiling are covered in stalactites, stalagmites and other speleothems of all sizes, among which it is worth mentioning the most impressive one, Colonna Ruggero, that is 12 metres in height.
Once you have walked through the main cave you get to a ledge, along the Carlo Finocchiaro pathway, and you then reach a short, artificial tunnel which leads to a belvedere, offering a magnificent view of the immense chamber below. Just a few metres up and, after going through a wide, natural gallery, where you can see the skeleton of a cave bear, you get back to the surface. The Grotta Gigante is also an important underground scientific research centre (Pendulums, Seismographic Station, Archaeological excavations, Flora and fauna research centres, Muon radiography, Radon monitoring) and surface scientific research centre (Climatological Observatory of the Karst, Epigean station for the measurement of karst dissolution). The cave is open all year round, with different opening hours according to the season. Closed on 1 January, 25 December and every non-holiday Monday. Open every day in July and August. The Grotta Gigante has been open to the public for over 100 years! The tour of the cave is always accompanied by a guide and lasts about an hour.
The temperature inside the cave is of 11°C all year round and the path is safe, built on a human scale and made up of 500 steps going down and 500 steps going up. In the multimedia room of the Visitors Centre it is possible to carry out a virtual tour of the cave, thanks to the new laser scanning technology of the Grotta Gigante.