The night sky above the World Heritage site of Meteora. Constellation Cassiopeia and the Double Star Cluster in Perseus are on the left. On the right the elongated halo 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".