A remote archipelago in the South China Sea has come under an extraordinary amount of scrutiny lately. Here, China is building up small reefs and atolls into whole artificial islands—all in hotly disputed territory. In the clearest sign yet of its military intentions, one of those islands now has an airstrip.
More than 70 percent of the surface of the Earth is covered by water: oceans, seas, rivers, and lakes. Sometimes humankind just can't get enough dry land to set foot on, so we create artificial islands for our needs.