These cliffs are stupendous and the views from them AND of them are really special. You can drive along the road--there's only one road and there are some pull offs along the way. The road is very narrow, has hairpin turns, and should not be driven at night. From the road, you can access various trails (get a map from TI in Porto or Piana). The hike to the Fortress is moderately difficult and has excellent views.
Otherwise, the Calanques can be seen from the various boat rides leaving from the Porto Marina.
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