The only element of the ancient complex of defensive walls and castle erected between 1325 and 1357 by the Visconti family, which remained unscathed by the total demolition carried out in 1809, the Tower looks like a quadrilateral built on the river, used as a prison from its construction until the second half of the 18th century. The typology of its cells made it famous by the name "Forni".
First experimenter was its builder Galeazzo Visconti himself, locked up with his brothers and sons for nine months by his former ally Ludovico il Bavaro. Visible in the tower are the slits of the drawbridge, a Gothic mullioned window and a stone coat of arms of Charles II of Spain.
