A photo of The Head of Medusa (in German, Das Haupt der Medusa). The painting was done by the artist Michelangelo Merisi da Caravaggio around 1597. Caravaggio made the painting on an actual shield, in a nod to the Medusa story. It's now part of the collection of the Uffizi Gallery in Florence, Italy.  

(Image via Wikimedia Commons, reproduced here under a Creative Commons 3.0 license.)