What Are These Huge Concrete Arrows in the Desert For?...
During the late 1920s and early 1930s, the US Department of Commerce created an air mail route between Los Angeles and Salt Lake City. These enormous arrows helped pilots stay on course. The historical society of Washing...
http://www.neatorama.com/2013/05/02/What-Are-These-Huge-Concrete-Arrows-in-the-Desert-For/



