Exploring the Frasassi caves, Italy's largest and most famous complex cave system
One hour from Ancona, in the Marche region, is the town of Genga; with a population of less than 2,000 people, the Gengarini are literally standing on top of one of Europe’s most spectacular sights: Grotte di Frasassi. You can easily imagine yourself to be in a Jules Verne novel as you travel through the Frasassi caves, Italy's largest and most famous complex cave system. Dating as far back as 180 million years ago and extending for 35 km, this subterranean world of calcareous rock formations first opened to the public in 1974, and visitor numbers have just passed the ten million mark; that’s an impressive average of 256,400 people each year.[...]
Via Mariano Pallottini
How are caves formed, and how do they endure for so long?