Now in its third year on the trail, The Discovery Expedition of St. Charles, Mo., has traveled more than 4,100 miles on the Ohio, Mississippi, Missouri, Snake and Columbia rivers. The group is re-enacting the more than 8,000-mile expedition of Meriwether Lewis and William Clark, which was commissioned in 1803 and ended in 1806.

On this 21st century journey some have flipped their boats; others wintered in a cabin so cold the snow never melted off a woodpile stacked inside; and some volunteers hunted buffalo with flintlocks. One of the very few injuries so far involved a hunting knife and an apple — not pretty.