The Grotta Gigante
One of the largest show caves in the world
On the Carso, the limestone plateau that rises behind Trieste, in the municipality of Sgonico, the Grotta Gigante is one of the largest show caves in the world, and the one with the largest single chamber accessible to tourists: an immense underground hall about 107 metres high, 65 metres wide and 130 metres long, so large that, according to a famous comparison, it could contain St Peter's Basilica in Rome. In 1995 it was entered in the Guinness Book of Records as the largest tourist cave. It was formed over millions of years by the action of water, which dissolved the limestone of the Carso, giving rise to the karst phenomena that take their name from this region.
The visit, with a guide, lasts about an hour and follows a path of about 500 steps down and up, through the great hall, among huge stalagmites, some more than ten metres tall, columns, curtains and concretions of every shape, including the "candlesticks", flat-topped stalagmites formed by the water dripping from the very high ceiling. The cave is also an important scientific site: two very long geodetic pendulums, about 100 metres long, hang from the ceiling, among the longest in the world, used to measure the tiny deformations of the Earth's crust. The temperature inside is about 11 °C all year round. Next to the entrance, the Museo di Speleologia illustrates the history of the exploration of the karst caves and their fauna.
Tip: bring a sweater even in summer; combine the visit with a walk on the Carso and a stop at an osmiza, a farm selling its own products.
Where it is
More things to see in Friuli Venezia Giulia
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