““Far less tragic—and certainly less attention-grabbing—was a second, very profound event that also happened in 2008. Its exact timing will never be known, but at some instant during the year, the number of people living in urban areas grew to briefly match, for a few seconds, the number of people living in rural areas. Then, somewhere, a city baby was born. From that child forward, for the first time in our history, the human race became urban in its majority.””