The romantic image of pioneers riding in covered wagons across the plains is almost entirely fiction. Prairie schooners had no springs and were built for cargo, so nearly every man, woman and child walked the roughly 2,000-mile Oregon Trail on foot, covering close to a marathon a day for months. This episode strips away the video game and Hollywood myths to look at the diaries and historical data behind why more than 400,000 people chose this brutal journey between 1840 and 1869.

The story begins with fur trader Robert Stewart stumbling onto Wyoming’s South Pass in 1812, a route that sat unused for decades until the collapse of the beaver-pelt hat market left skilled mountain men unemployed and looking for work as guides. From there the conversation covers the mule-versus-ox debate, the ordeal of shoeing an ox, the graveyard of abandoned furniture at Camp Sacrifice near Fort Laramie, cooking with buffalo chips, the way the trail upended Victorian roles for women, and the invisible killers, cholera and scurvy, that claimed far more lives than any dramatic attack.

• Why Lewis and Clark’s route was useless for wagons, and how a fashion shift from beaver felt to silk hats opened the trail to families
• How the Great Plains came to be labeled the Great American Desert, pushing settlers all the way to Oregon
• The economics of ferries, toll bridges and Mormon scavengers who recycled discarded stoves and anvils for Salt Lake City
• How contaminated freshwater springs along the Platte River turned the 1849 to 1855 cholera epidemics into a daily terror
• The abrupt end of the era when the transcontinental railroad turned a five-month walk into a seven-day, $60 train ride in 1869