All over the world, citizenship—the right to belong somewhere—is tied to nation-states. If you don’t belong to one, it’s almost as if you don’t exist. However, there was once a time when nothing was more natural for our ancestors than to move around, discover new horizons, and share what they had with each other. With the development of agriculture, though, people began to settle and claim their own land and possessions. They clustered in villages and towns, shifted from foraging to farming, and came to rely on bureaucrats and sovereigns to manage their lives, to keep them safe. And they let those in charge become wealthy and powerful.