Villefranche-sur-Mer sits on one of the deepest natural harbours in the Mediterranean, which is why cruise ships now anchor where fishing boats once did. Its old town is a tight maze of covered stairways and pastel buildings running straight down to the water, watched over by the 16th-century Citadelle Saint-Elme.
Don't miss the small waterfront Chapelle Saint-Pierre, decorated inside by Jean Cocteau, or the view from Cap Ferrat's coastal path just next door. It's one of the smallest towns on this list, but its beach and harbourside restaurants make it an easy, low-key base for exploring the whole bay.