Because of its high mountains, dry air, and relative lack of air pollution, Chile is a mecca for astronomers. European astronomers have planted their telescopes there since 1969.
La Silla, a mountain close to the town of La Serena, was the first site in the country to house a European telescope. Even today, the mountain remains littered with telescopes that belong(ed) to various European countries.
This is unique because in the late 20th century, telescope technology allowed only for relatively small telescopes of about 3.2 feet in diameter—sizes that are huge for non-professional astronomers, but tiny for those who are used to 28-foot or even 35-foot telescopes.
Many of the small telescopes on the mountain are no longer used or have been replaced by robotic scanners that work in tandem with other small telescopes to look for exoplanets or supernovas. The largest telescope present is the monstrous 3.6m telescope and the ESO New Technology Telescope (NTT) that are both still very popular among astronomers in taking astronomical spectra.
Know Before You Go
There are weekly tours to the mountain that are free of charge, which allow you a chance to visit the NTT and the 3.6m telescope and get general information about the site in the visitor center. You have to book well in advance though (some suggest about 6 months) and re-confirm 10 days before the visit.