Call them what you will — aits, isles, atolls, cays, keys, islands, reefs, shoals, even continents — there are millions of them across the globe. The name that I particularly like to describe the smallest of these patches of raised land surrounded by water, very wet marshes, and in some cases even by sand, is hammock, from the Spanish hamaca. We have a lot of them right here in our own backyard.