Archaeologists studying an ancient mosaic found by workers laying cable south of Rome have been astonished to discover that it is an optical illusion.
Viewed one way up it is a bald old man with a beard, but turned the other way round it is a beardless youth.
Roberto Cereghino, a government archaeological official, told the Italian daily newspaper Corriere della Sera that it was "a very beautiful work, of immense significance".
Dang it, no picture.