La Silla Observatory is an astronomical observatory in Chile, some 150 kilometres (93 mi) northeast of La Serena. On this site, at the outskirts of the Atacama Desert, are three telescopes built and operated by the European Southern Observatory (ESO) as well as several other telescopes partly maintained by ESO. The observatory is one of the largest in the southern hemisphere and the first in Chile to be used by ESO.Photograph: ESO/F. Kamphues