The Horsehead Nebula, found in the constellation Orion, is probably one of the most identifiable nebulae in the sky. It is part of a dark molecular cloud, and is shaped like - you guessed it - a horsehead. It is visible as it is in front of a larger red diffuse nebula (IC 434) which consists mostly of hydrogen.

It is located near Alnitak (or Zeta Orionis), which is the easternmost star in Orion's Belt, and whose radiation causes the background nebula to glow.

It is approximately 1,500 light years away.