Building a wall along the U.S.- Mexico border has been a contentious subject in this year’s U.S. presidential election.
In parts of California and Arizona, a wall already exists.
It runs across rocky deserts, flowing sand dunes and miles of agricultural land. The wall splits towns and families, marking a boundary between two countries that used to be one. Busy land ports of entry and signs written in both Spanish and English attest to an interdependence that still exists in the bifurcated cities, faded mining towns and eccentric art outposts that punctuate the arid landscape.