Signs marking the entrance to the Pine Ridge Indian Reservation in South Dakota make it clear when you're literally "off the reservation," but the figurative meaning of the phrase has shifted over time. Kristi Eaton/AP hide caption

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Scottish explorer Mungo Park was among the first Europeans to view the Mandinka tribe's masked dancers who were known as Maamajomboo. He translated the word as "mumbo jumbo.' This 1797 illustration from Park's book, "Travels In The Interior Districts of Africa" shows a view of Kamalia village in Mandinka country. DeAgostini/Getty Images hide caption

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An 1852 illustration shows Snow White's evil stepmother gazing into her magic mirror. Her famous question includes an ambiguous word: "fairest." Project Gutenberg hide caption

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Slave auction in New Orleans, 1842, "Sale of Estates, Pictures and Slaves in the Rotunda, New Orleans." The nation's most active slave market was in New Orleans. Slaves who had been "sold down the river" were auctioned off to plantation owners. Encyclopaedia Britannica/UIG via Getty Images hide caption

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The Carlisle Indian Industrial School became a model for dozens of other boarding schools for Native Americans. The government would eventually make attendance compulsory for Native children. Library of Congress hide caption

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