A British art historian’s painstaking study of the cathedral in Santiago de Compostela uncovered a medieval prank.

He is a medieval in-joke, a male figure carved in the early 12th century for one of the world’s greatest cathedrals, but no one has known of his existence until now. The figure has gone unnoticed by millions of worshippers who have made the long pilgrimage to Santiago de Compostela in Galicia, north-western Spain over the centuries. He has looked down on them from the top of one of the many pillars that soar upwards, each decorated with carved foliage, among which he is concealed.
Now he has been discovered by a British art scholar who believes that he was actually never meant to be seen because it's a self-portrait of a stonemason who worked on the cathedral in the 12th century. She discovered the figure whilst conducting an intricate survey of Santiago de Compostela cathedral, a UNESCO world heritage site.

“You find this in medieval buildings,” Dr Jennifer Alexander told the Observer. “They’re usually in dark corners where only another stonemason would find them. This one is in a bit of the building where you’d have to be a stonemason to be up there to see it. It’s tucked away in among a whole set of capitals [the top of a column] that are otherwise plain. It’s just such a charming connection between us and the person that carved it. It’s almost as if it was designed just for us to see it by those people working on the building. Of course, this stonemason probably had no idea that he’d have to wait so long to be spotted.”
Despite the supreme talent of such craftsmen, they were completely anonymous, their names lost to history. This is the closest the mason got to signing his work.