Skip to main content

Subscribe to Smithsonian magazine and get a FREE tote.

Rachel St. John

Rachel St. John is a professor at UC Davis and author of Line in the Sand.

A metal obelisk marked the international border in Ambos Nogales circa 1913. American (left) and Mexican (right) sentries patrolled the line.

The Raging Controversy at the Border Began With This Incident 100 Years Ago

In Nogales, Arizona, the United States and Mexico agreed to build walls separating their countries