This Unesco Biosphere Reserve just off the coast of Basse-Terre makes for a superb day trip. A chain of small coral islets sitting atop a 25km-long coral wall, the reserve supports unique ecosystems including mangrove forest, rich birdlife and reefs bursting with tropical fish. There are also some gorgeous white-sand beaches, and you'll never have to worry about overcrowding. Book through an agency in Ste-Rose.