San Fruttuoso is a 13th-century Benedictine abbey hidden in a tiny inaccessible cove on the western side of the Portofino promontory. There is no road. You arrive by boat from Camogli, Portofino, or Santa Margherita, or you walk the rough coastal path over the headland in two and a half hours.
The reward is one of the most romantic medieval sites on the Ligurian coast: a Romanesque church, a Doria cloister, a tiny beach in front, and almost no buildings visible besides. In summer ferry season the cove is busy; outside that it is genuinely remote.