Exploring Turks and Caicos Islands feels like tripping down Alice's rabbit hole: It's under British rule, but the currency is the American dollar. Traffic moves on the left, but most rental-car steering wheels are on the right. And you won't find a single McDonalds or KFC. What you will find is one of the world's most stunning shorelines, Grace Bay Beach. The 12-mile porcelain-white crescent of sand is fronted by the kind of turquoise and beryl-hued colors that Instagram dreams are made of. The color and clarity come partially from the crushed pink coral sea bottom, found only in this part of the South Atlantic. A protective barrier reef enables safe lagoon swimming for kids, easy snorkeling, and excellent diving and bonefishing. But should you wish simply to relax, the vibe is all about tranquility—more beach chic exclusive than overdeveloped. Although numerous resorts have opened on Providenciales (really the only island developed for tourism), there are just two small shopping centers, and hotels here blend into their natural environs.