La Silla by night

This image shows a collection of the many telescopes that live at ESO's original observatory, La Silla, which is located at an altitude of 2400 metres in the Chilean Atacama Desert. This site offers excellent viewing conditions, with around 300 clear nights per year, a major factor in the decision to build La Silla there. La Silla became the largest astronomical observatory of its kind, and many of its telescopes have paved the way for new kinds of astronomical technology; the New Technology Telescope (NTT) was a forerunner of the Very Large Telescope (VLT), while the Swedish-ESO Submillimetre Telescope (SEST) paved the way for APEX and ALMA. La Silla celebrates the 50th anniversary of its inauguration this year (2019), and remains among the most scientifically productive observatories in the world.