Spurred by team spirit after a win over Pomona College in 1914 it was decided to turn Sentinel Peak into "A" Mountain. And thanks to students who used horse drawn wagons to haul water and mortar to the site, the "A" was built. Work was completed in 1916. The "A" is painted with UA colors (red and blue) and occasionally students from rival Arizona State University put their own colors on it in a clandestine night operation!
The image is from a postcard of Tucson, circa 1930's.