Dellis Cay

This stunning small island, the second-to-last cay in the string of small islands between Providenciales and North Caicos, has a gorgeous sandy beach and good snorkeling; it's also a good place to search for sand dollars. It's currently uninhabited, but looks ominous with its partially built Mandarin Oriental Resort, which was abandoned when the economy tanked—the shells of buildings can be seen from miles away. Its future is uncertain as of this writing. If you're visiting by private boat, it's still worth a stop just for the many unusual seashells.