Grotta Gigante (also known as Grande Caverna or Great Cavern), a giant karst cave located just some 15 kilometres from Trieste, has entered the Guinness Book of Records in 1995 as the world’s largest tourist cave. Its estimated age is about 10 million years.
The only way to get inside the caves is to pass a downhill tunnel with 500 steps. Grande Caverna’s (Great Cavern) depth from the ground level is 120 metres, and during the visit people have to walk 100 metres downwards. This huge cave is oval-shaped and has a volume of 400000 cubic metres. Other dimensions are impressive as well, the cave is 167 metres long, 76 metres wide and 98 metres high.
The floor and the ceiling are covered with stalactites, stalagmites and other speleothems of different sizes. The most impressive one, Colonna Ruggero, that is 12 metres high, is definitely worth mentioning here.