Building walls may have allowed civilization to flourish
Humans have built walls to keep others out, or in, for at least 12,000 years. Why is wall building coming back into fashion now?
If it is ever built, President Donald Trump’s much-vaunted wall, which is supposed to stretch for nearly 2,000 miles along the United States’s border with Mexico, would be the largest infrastructure project since the U.S. highway system, estimated to cost $18 to $40 billion. But as David Frye reveals in his new book, Walls: A History of Civilization in Blood and Brick, the idea of constructing barriers to keep others out—or, in the case of the Berlin Wall, to keep people in—is as ancient as human civilization. Only the people being shut out have changed.
When National Geographic caught up with Frye by phone at his home in Connecticut, he explained how the ancient world was split between