Morro Dois Irmãos, Fernando de Noronha, Brazil

A distinctive duo

Dramatic volcanic features like these twin sea stacks, known as Two Brothers Rock, make this archipelago easy to spot from afar—a lucky thing, given how out-of-the-way it is. Lying a couple hundred miles from the Brazilian mainland, the main island of the Fernando de Noronha group is the only inhabited one in the small chain. Despite its tiny size (well below 10 square miles), it's jam-packed with rugged terrain and relaxing beaches alike. Even more treasured is what surrounds the isle: In 2001, UNESCO declared Fernando de Noronha a World Heritage Site to protect the thriving undersea life that feeds here.