Credit for this image: T.A. Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA) and Link to the original image.
The Horsehead region is one of the most famous parts of the sky. Located in the constellation of Orion, the horsehead is actually a "dark" nebula, that is, a cloud of obscuring dust that lies in front of the pink nebula. It cuts out a "hole" in the shape of a chess piece.