Civilization marks its beginnings to the moment, more than 14,000 years ago, humans first gathered into settlements, leaving behind their days as nomadic hunters and gatherers. Known as sedentarization, this phenomenon likely debuted in the Fertile Crescent of the Levant, followed by the Yangtze and Yellow River basins two millennia later, and eventually in Mexico, South America, and finally the eastern shores of the United States. At each point sprang up villages, cities, and, eventually, nations. Over thousands of years, fixed boundaries were codified and defended, often at great cost. Many borders have been drawn wisely, following natural formations like barriers of mountains or rivers. Many follow linguistic, ethnic, religious, or tribal boundaries. But others have been haphazardly imposed by outsiders with the stroke of a pen on some distant map. As empires fell and the speed of global trade and...

You do not currently have access to this content.