Rich copper mines transformed Bisbee from a rough camp in the late 1800's to one of the largest and most cultured cities between St. Louis and San Francisco by the early 1900's. From the discovery of rich surface deposits in 1877 until 1975, when the last underground mines closed, Bisbee's mountains yielded more than 8 billion pounds of copper, as well as gold, silver, lead, and zinc, making it one of the most productive mining districts in the world. The wealth generated by copper mining built expansive business and residential districts and was responsible for untold contributions worldwide.