The Alidosi Bridge on the Santerno river, with its 42-metre long single arch, is a splendid example of a Renaissance age humpbacked bridge. Commissioned in 1499 by the Alidosi family, it came to symbolise the family’s power and wealth. This important thoroughfare, which was restored several times over the centuries, was a boon to traffic in the Santerno Valley, making Castel Del Rio a vivacious center of commerce.
There a five rooms inside the bridge that where originally used to collect tolls and to hold prisoners. Recently these rooms were renovated and opened to the public as an exhibition space.
The structure was named a national monument in 1897.