The longest river of Southern Italy with its 175 kilometres rises in Molise, at Rocchetta a Volturno and runs for a long way in the Apennine region, of which, after the Ponte 25 archi, marks the border with Campania.

On its shores violets grew, and this is why the Greeks called it Clanis. The River Clanis rises on Mounts Tifatini.

It rises at the foot of Mounts Trebulani, at 86 meters above sea level, in the territory of Calvi Risorta.

For the ancients, it was the river of the myth, which gave forgetfulness to whoever drunk its water.

It rises from Lake Matese and in the first part of its way, it is characterised by cascades and differences in heights.

For the ancient Italic peoples it was a sacred river. On the shores, they erected sanctuaries such as the Demetra and Teano one.