The European Extremely Large Telescope is to be built on Cerro Armazones, a mountain 3060km in altitude at its peak and 20km away from the other European Southern Observatory big telescope at Cerro Paranal, the Very Large Telescope.
The decision to park them so close to one another has nothing to do with a personal preference for Chile or a lack of contending sites, the area just happens to have excellent observing conditions and in the end this and the ability to operate in sync with Paranal Observatory, was the clincher in deciding between it, several other Chile sites and a place in Spain. The Chilean Government has agreed to donate a substantial amount of land to the project, which extends from ESO’s Paranal property and covers Cerro Armazones. The idea of this is to prevent encroaching light pollution or mining activities.
The E-ELT will be a forty-two metre optical/infrared telescope. Construction is expected to begin by the end of the year with around eight years wait before the telescope comes online. Further information here.