The River Wave of Monte Biron, near Cattignano di San Giovanni Ilarione, is a phenomenon that originated in the Oligocene, about 40 million years ago.
Many limestone rocks shattered under the thrust received from below for the rise of the seabed, while others resisted intact, like this wall on the northwest side of Mount Biron.
Subsequently, due to the erosion caused by the continuous breaking of the sea waves over millions of years which continued to crash against the limestone coast, the rock was modeled with this unmistakable wave shape.
In the following periods of prehistory it also became a refuge for the first inhabitants of the valley.
Summary taken from "The river wave of Monte Biron" by Luciano Vanzo published on "5 Comuni Alpone" n. May 6-Jun 2009
copy paste text taken from facebook page: NaturaSì San Bonifacio