On my list:

The blue hole of Hanawa is hidden near the road before the Col du Casse-Cou going up to the north of the island, in the narrowest part of the isthmus that marks the boundary between the districts of Fayaoué and Saint-Joseph. This petrol-blue colour circular pool of 30 m in diameter is supplied with seawater through cracks in the coral. A magical site, with soothing beauty, which serves as a bathing place for the children of the tribe and a refuge for sea turtles. A team of divers of Jacques Cousteau, the French underwater explorer dived here but never managed to reach the bottom. A little further and hidden in the vegetation, is a second less easily accessible water hole.