The ruined castle that crowns the medieval upper town is Campobasso's most visible landmark, visible from most of the city and reached by a steep climb through the old quarter. Built by the Monforte family in the mid-15th century on the foundations of a Lombard stronghold, it is more ruin than monument: the walls are largely intact but the interior is open to the sky. What you come for are the views — on a clear day you can see across the rolling Molisan hills in every direction, with no modern development to interrupt the horizon.
The climb through the old town is as rewarding as the castle itself. The lanes that wind up past the church of San Giorgio and San Bartolomeo are essentially unchanged from the medieval period, with stone staircases, carved doorways, and the occasional cat sleeping in a patch of sun.