The Cerro Paranal Observatory at dusk. One of the auxiliary telescopes of the Very Large Telescope Interferometer opens its enclosure to prepare for the night. On the background of this telephoto image is Cerro Armazones, a 3,064 m (10,052 ft) mountain and the site for the European Extremely Large Telescope (EELT), the 39.3-meter telescope that will be the world's largest optical telescope in 2020s.