The First Cities

For almost the entire human story there are no cities — only small bands, moving, following the food. Then, in a handful of river valleys, people do something risky and new: they stay. They plant, they store, they crowd together in numbers that should not work. Out of that crowding pours everything you call ordinary — writing, kings, money, walls, war, a town with no streets, a wall held for a hundred days. And we are still arguing about why, after a million years of wandering, we suddenly chose to stop.