This week marks the 50th anniversary of one of the world’s leading astronomical institutions, the European Southern Observatory. In honor of ESO’s birthday, we take a look at some of its most stunning shots of the night sky, amazing objects in space, and the organization's beautiful telescope facilities. ESO started when astronomers from five European countries – Belgium, France, Germany, the Netherlands, and Sweden – came together on Oct. 5, 1962 to build a telescope in the Southern Hemisphere. Having a large telescope south of the equator gave these member states access to unprecedented clear skies and celestial objects that simply can’t be seen from the Northern Hemisphere, such as the Magellanic Clouds. Over the decades, many more countries have joined, including Denmark, Switzerland, Italy, Portugal, the United Kingdom, Finland, Spain, the Czech Republic, Austria, and, in 2010, Brazil, which became the first non-European state to join. The 15 member countries produce roughly 750 scientific papers annually using data from the organization’s world-class telescopes. ESO currently has eight telescopes at its disposal, including some of largest and most advanced ground-based facilities, such as the Very Large Telescope, the New Technology Telescope, and the Atacama Large Millimeter Array. All of its instruments are located in Chile, on the mountaintops of La Silla and Paranal, and the plateau of Chajnantor in the Atacama Desert. The organization is currently constructing what will be the biggest telescope ever, the European Extremely Large Telescope, a behemoth instrument with a 130-foot-wide primary mirror, as wide as a 15-story building is tall. Scientists working for ESO have delved into some of the deepest astronomical mysteries, such as the nature of dark matter and energy, the origin of gamma-ray bursts in the universe, the characteristics of the supermassive black hole at the center of our galaxy, and the search for exoplanets and life outside of Earth. As part of its birthday celebrations, ESO will host a 6-hour live webcast on Oct. 5, when the Very Large Telescope will be pointed toward the Thor’s Helmet Nebula, a target chosen by members of the public. The organization has also released The Jewel on the Mountaintop, a history book covering its first 50 years, and Europe to the Stars, a coffee-table book featuring incredible images of telescopes and space, which can be downloaded for free. Above: Beautiful Orion The famous Orion Nebula tops the list of what ESO considers their 100 best images. The amazing shot shows off swirling gas and dust in this star-forming region. Many of the mind-blowing pictures on ESO’s Top 100 list have previously been featured in Wired’s Space Photo of the Day. Image: ESO/J. Emerson/VISTA

The Very Large Telescope Made up of four individual instruments, each with a 26-foot mirror, the Very Large Telescope is one of the world’s best ground-based telescopes. Standing high above the world on Cerro Paranal, the VLT can detect objects about four billion times fainter than the human eye. Image: ESO

Lagoon Nebula One of ESO’s incredibly large starscapes, this image shows the Lagoon Nebula in a full 370 million pixels. While the nebula’s light is too faint to be visible in the night sky, if you could see it with your eyes, it would be eight times larger than the full moon. Image: ESO

Carina Panorama This area of churning star formation is known as the Carina nebula, and it can only be seen in the Southern Hemisphere. Glowing lanes of gas and dust form beautiful shapes, in which young stars are created. Image: ESO/T. Preibisch

Night Sky Over La Silla The Milky Way glows brightly over the MPG/ESO 2.2-meter telescope on the La Silla Ridge atop Paranal. La Silla is located far from pollution and is high above the clouds, offering some of the best conditions for viewing the stars. Image: ESO/José Francisco Salgado

Helix Nebula This image shows the Helix Nebula, a planetary nebula formed from the dying gasps of a star like our sun. The central blue-green glow comes from oxygen atoms shining under the intense radiation of the 120,000-degree central star, while the outer reds come from nitrogen and hydrogen. Image: ESO

Auxiliary Telescopes Three of the Auxiliary Telescopes at Paranal look up at the stunning night sky. Countless stars can be seen as well as some incredible objects, such as the glowing red Carina nebula. Image: ESO

Paranal Starscape This amazing picture is a vista composed from a truly shocking 340 million pixels, taken as part of ESO’s GigaGalaxy Zoom project. Taken with the Very Large Telescope, the image shows off the central parts of the Milky Way galaxy and some famous objects, including the Trifid Nebula. Image: ESO/S. Guisard

Star Trails A time-lapse exposure shows the movement of the heavens over several hours. The star trails appear because of the rotation of the Earth, which sweeps through the night sky, while ESO’s telescope facilities stand watchfully below. Image: ESO/J. Pérez

Christmas Tree Cluster Taken at ESO’s La Silla Observatory, this image features a region of space 30 light-years across. Contained within it are the beautiful Christmas Tree star cluster and the Cone nebula. Image: ESO