The ruined castle on Monte Ursino looms above the old town, reachable by a trail that winds through pine and olive groves. The climb takes about 30 to 40 minutes from the town centre and is worth every step: from the towers you look down over the medieval rooftops and the curved beach, with the cape to the west and the coastline stretching east toward Savona and Genoa.
The fortress dates from the 12th and 13th centuries, built when Noli was a functioning maritime republic with territory to protect. Much of the structure is ruined, but several towers still stand and the circuit of walls can be traced. The walk up also passes a small 13th-century church, the Oratorio di San Lazzaro, worth a look on the way. The path is not always well-signed; ask in the town for the most reliable route up and bring decent shoes.