Wall-E fell in love with another robot in the movie named after him. Researchers have yet to create a sentient machine, but a breakthrough could be on the horizon. John M. Heller/Getty Images hide caption

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A capuchin monkey riding a dog. Tim Lepard, owner and creator of the Monkey Rodeo, says his animals are treated humanely. Courtesy of Tim Lepard hide caption

toggle caption Courtesy of Tim Lepard

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