The first volcanic activity on Etna took place about 500,000 years ago, with eruptions occurring under the sea off the ancient coast of Sicily.
The volcano formed in the direction of the western axis, and as a result of later eruptions and the filling of the bay with solidified lava, a volcanic cone named Callanna was formed (about 168-100 thousand years ago).
In the following years, the cone Trifoglietto I was formed, which was covered by Trifoglietto II (about 80-64 thousand years ago). The collapse of Trifoglietto II led to the formation of the Valle del Bove caldera.
