More than 400,000 people traveled the Oregon Trail during the 19th century—so many that there are spots where wagon ruts are still visible. This photo was taken at Three Island Crossing, better known to children of the 1980s as the Snake River Crossing. (Don't ford it! Never ford it!)

When I first saw this photo, taken by Flickr user gharness, I thought, "No freakin' way." But, I've been assured by both the Associated Press and Idaho State University that this is for real. Wagons really did wear down certain patches of ground so much that nothing grows there to this day. The National Parks Service, Bureau of Land Management and other groups have marked many of these spots (you can see a marker in the above photo on the right) and have taken steps to preserve them. Mind-blowing history.

(Via Johanna Harness)

Image used via CC