Many of the hikers, climbers and skiers who come to the Northern Grigna in every season will have wondered at the countless holes dotted all over the surface of the mountain and asked themselves where they lead. Formed by the chemical reaction of water acidified by the CO2 on the Grigne’s calcareous and dolomitic rocks, some of these caves stretch over several km, and can be over 1000 m deep: this makes the Grignone one of the most important karstic areas in Italy, with some of the deepest caves in Europe.
The cavities are often vertical, like this one on the Grignone photographed by Lorenzo Rossato.