You don’t have to go out of the port, you are already in the calanques! From the end, on 1km, you can find two pontoons to reach the boats and at half-way the Harbor’s office. Then the calanque becomes natural again.
The cliffs and the old hoppers (big funnels) on the seaside are from the old Solvay quarry, that was exploiting the limestone to make whitewash from 1900 to 1981. The limestone was extracted with dynamite, then crushed to be loaded on the boats waiting in front of the hoppers.