In 1916 , Pancho Villa crossed the U.S. border .
In 1916 , Pancho Villa attacked the town of Columbus , New Mexico ; this was the sole invasion by a foreign armed corps of the continental U.S. in the 20th century .
In 1916 , Pancho Villa crossed the U.S. border and attacked the town of Columbus , New Mexico ; this was the sole invasion by a foreign armed corps of the continental U.S. in the 20th century .