At its inception in 1860, the Pony Express operated between St. Joseph, Missouri—the western end of a telegraph line—and Sacramento, California. Changing horses at stations roughly 10–15 miles (16–24 km) apart, riders carried the mail a distance of 1,800 miles (2,900 km) in about eight days, often traveling through hostile Native American territory. Though it provided an important mail link with the West, it was a financial failure, and the Pony Express announced its closure two days after what? Discuss