When:
Lookups spiked on April 15, 2015.
Why:
An online contest to find "twin strangers" - people unknown to each other who look alike - resulted in a remarkable first-time meeting of women who have nearly identical features. Media coverage called them doppelgängers.
Doppelgänger means "someone who looks like someone else" or "double." It originally meant "a ghostly counterpart of a living person" and can also mean "alter ego." It comes from the German words that literally mean "double goer."