Dutch artist Han van Meegeren is known for his forgeries of Johannes Vermeer's paintings, and "Christ and His Disciples at Emmaus" may be the most famous -- or infamous -- fake in his repertoire.
Van Meegeren was a skilled artist in his own right, but he never denied his forgeries even after they were sold into the art world (allegedly as part of an Old Masters collection). His work "Christ and His Disciples at Emmaus" was probably painted in 1936, and certified as a legitimate Vermeer in 1937 by art historian Abraham Bredius, who declared the find an untouched masterpiece from Vermeer's hand after two days of consideration. Bredius' verdict was published in Burlington Magazine.
"Christ and His Disciples at Emmaus" went on to sell for a hefty price, as did many of van Meegeren's forgeries at the time -- he's thought to have made about $30 million (adjusted for today's dollar) [source: NPR]. The fake Vermeers weren't exposed until 1945, when the sale of the fake "The Woman Taken in Adultery" to the Nazi party's Hermann Goerin led authorities to van Meegeren, but not for what you might think. He wasn't being outed as a forger; he was charged with collaborating with the enemy. In a surprise twist, during his testimony the artist himself admitted he had forged the painting, as well as others.