Lewis And Clark Expedition

MAY 1804: A painting depicting explorers Meriwether Lewis and William Clark on their Keelboat known as 'The Boat' using poles to navigate the Missoiuri River in May 1804. (Illustration by Ed Vebell/Getty Images)

Poling in the Missouri Shallows. In May 1804 the Corps of Discovery was on the Missouri River in a keelboat whose sail often had to be reefed in favor of men using poles. (Ed Vebell/Getty Images)

Ed Vebell/Getty Images