The Emerald Sea -- Lark Trumbly

The Emerald Sea lies at the northern end of Madagascar, and Google searching reveals that it's as its name implies:

The closest city is Antsiranana, whose culture is an eclectic blend of French, Malagasy, East Africa, and India. Few tourists visit the area, except to kite surf -- it's apparently one of the best spots in the world. The water is warmest between November and March during the rainy season, but it's shallow enough to be swimmable year-round. To access the bay, one can either opt for an organized tour boat or hire a local fisherman, who will usually charge much less and know much more. Unsurprisingly, the Emerald Sea is considered to be one of the most beautiful natural areas in the world, and it's 10/10 on my bucket list now that I know it exists.