An impressive pentagonal tower, approximately 18 metres in height, built in the 15th century to defend the Cassero.
Despite a lack of documented evidence, the project is attributed to Francesco di Giorgio Martini, a Sienese architect who designed many fortification structures within the Duchy of Urbino.
It was partially restructured in the 16th and 20th centuries and today it contains as memorial dedicated to victims of the wars.
On the walls to the east of the Torre dello Sperone you will notice an opening dating back to the early 20th century, to facilitate the access of the first motor vehicles to the historic centre.