This photograph of the border region between Mexico and the United States—specifically, the two towns of Nogales, one in Sonora, Mexico, and the other in Arizona, United States—was taken in 1890 and is attributed to A. R. Reynolds. The white dotted line drawn onto the photograph shows where the nations agreed that the border should be, according to the terms of the Treaty of Guadalupe Hidalgo (1848), which ended the U.S. War with Mexico, and the Gadsden Purchase (1854). Without this line, the border is invisible, revealing one fluid region—a borderlands region. This region is sometimes called Ambos Nogales (Both Nogales) or Los Dos Nogales (The Two Nogales), suggesting the shared history and culture of these two towns.