Fadiouth, Senegal
Linked to the mainland by a narrow wooden bridge, Fadiouth (part of the village of Joal-Fadiouth) is almost entirely covered with clam shells. Inhabitants have been harvesting the molluscs for centuries, so discarded shells are literally everywhere - they have even been incorporated into the island’s architecture. A key trading post in the colonial period, the island is now reliant on tourism (and clams, obviously).