Delivering the mail in the old West was no easy task — check out the Pony Express employees' job description. Across 1,800 miles of wilderness, riders changed horses about every 12 to 15 miles. At each station, they would quickly take the mochila with mail pouches from the saddle and throw it onto the saddle of the fresh horse and hit the trail again. The Pony Express operated for only 18 months between April 1860 and October 1861, and most of the original trail has been obliterated either by time or human activities. However, approximately 120 historic sites eventually may be available to the public on the Pony Express National Historic Trail, including 50 existing stations or station ruins. An example: remains of the old hotel and Pony rider station at Pacific Springs in southwestern Wyoming.