Night sky near the morning twilight over the Cromlech of Xerez near Monsaraz village, Alentejo, Portugal. Venus uis rising at the horizon and the zodiacal light (reflection of sunlight from dust in the Solar System plane) is prominently visible. The location is a part of a Dark Sky Reserve area covering 3000sq km in southern Portugal. The Alqueva Dark Sky reserve is the first area in the world to be internationally certified as a Starlight Tourism Destination by the Starlight Foundation. The elongated stone circle is an array of 50 standing rocks with a central larger menhir. The smaller stones were found in 1968 and situated around the menhir and later moved to its present site, to protect them from flooding by the Alqueva dam which completed in 2002.