English: This panoramic image, taken by ESO Photo Ambassador Alexandre Santerne reveals a somewhat Martian-looking landscape. This dry, red scene could well be taken to be on another world, but is actually the site of the La Silla Observatory, 2400 metres above sea level, on the outskirts of the southern part of the Atacama Desert in Chile — and ESO’s first observing site.

With more than 300 clear nights per year, low atmospheric turbulence and dry conditions, La Silla offers some of the very best conditions for ground-based observational astronomy. For many years it was one of the most scientifically productive observatories in the world, and today still makes a significant contribution each year.

The main platform at La Silla, to the right in this image, hosts a huge range of telescopes with which astronomers can explore the Universe. The most striking is the ESO 3.58-metre New Technology Telescope (NTT) with its octagonal enclosure — the first in the world to have a computer-controlled deformable main mirror — a system known as active optics — and paving the way for modern large telescopes including ESO's Very Large Telescope (VLT) at Paranal. The site is also used by ESO Member States for targeted projects using a vast range of instruments scattered across the site, including the MPG/ESO 2.2-metre, the Danish 1.54-metre and TAROT telescopes.

To the left is the Swedish-ESO Submillimetre Telescope (SEST) — a 15-metre radio telescope built in 1987, then the only large telescope for submillimetre astronomy in the southern hemisphere. It was decommissioned in 2003 to make way for the Atacama Large Millimeter/submillimeter Array (ALMA) to further explore our cold Universe.