"Old Man With a Beard" is the name of the Rembrandt painting that, since the 1960’s, has been widely thought of as a fake. Now, with new x-ray technology, scientists have revealed that underneath that Old Man lies an unfinished self-portrait of the Dutch artist.

From the Guardian:

Doubters of its attribution had included leading specialists at the Rembrandt Research Project in Amsterdam. But the discovery now offers irrefutable evidence, according to Ernst van de Wetering, head of the project and emeritus professor of art history at the University of Amsterdam.