Painter William Henry Jackson's depiction of emigrants on the Oregon Trail passing the infamous Devil's Gate. With the Sweetwater River to one side and a rock face on the other, settlers had to pass through a narrow 30 foot path located nearly 300 high. Moving a covered wagon across the terrain was dangerous to the extent that settlers who successfully made the journey would often carve their name into the rocks on the passage's far side.
Images from: John D. Unruh, Jr., The Plains Across: The Overland Emigrants and the Trans-Mississippi West, 1840-60, 322. (Chicago: University of Illinois Press, 1979).