Traveling at sea for the first time is a chance to realize that the ocean is not one ocean. The water changes. The Atlantic that seethes off the eastern United States is glaucous and light- less and looks mean. Around Jamaica, though, it’s more like a milky aquamarine. Off the Cay- man Islands it’s an electric blue, and off Cozumel it’s almost purple. Same deal with the beaches. You can tell right away that south Florida’s sand comes from rocks: it hurts your bare feet and has that sort of mineralish glitter to it. But Ocho Rios’s beach is more like dirty sugar, and Cozumel’s is like clean sugar, and at places along the coast of Grand Cayman the sand’s texture is more like flour, silicate, its white as dreamy and vaporous as clouds’ white. The only real constant to the nautical topogra- phy of the Nadir’s Caribbean is its unreal and almost retouched-looking prettiness. It’s impos- sible to describe right; the closest I can come is to say that it all looks: expensive.