The Calieroni are a series of natural pools with crystal-clear, exotic-looking water, connected by lively waterfalls: a small and charming hidden treasure nestled among the tightly packed houses of Valstagna overlooking the eponymous stream.
The circular potholes have been shaped over millennia by two phenomena: mechanical action, in which rocks and pebbles carried by the swollen river swirl, creating a centrifugal effect that erodes the surrounding rock; and chemical action, in which the carbonic acid in the water dissolves the calcium in the limestone, eroding it.
The Calieroni take their name from rural Venetian tradition: the dialect word 'caliera' refers to a large pot (usually made of beaten copper) used to make polenta for the whole family... the shape of the round cavity resembles a cauldron filled with water!
When water levels are low, you can reach the Calieroni by abseiling down into the stream bed, either from the mountain or from the small bridge downstream. This route requires caution due to the smooth, wet rock. In the summer, they become a natural swimming pool with icy waters, popular with the young people of Valstagna.