The night sky above the World Heritage site of Meteora. The elongated halo on the upper right is the Andromeda Galaxy or M31; the Milky Way's neighboring spiral galaxy, home to over one trillion stars. Meteora is a historic complex of lofty bizarre monasteries which are built on (or inside) giant natural sandstone rock pillars. Some are about a thousand years old. The name Meteora means "middle of the sky" or "in the heavens above".