In the world of high-powered telescopes, where rival institutes jostle to claim the 'biggest,' 'most powerful' or 'most technologically advanced' specimens, Paranal is right up there with the big boys. This groundbreaking observatory has a Very Large Telescope (VLT) consisting of an array of four 8.2m telescopes – for a time at least, the most powerful optical array in the world.
The Cerro Paranal Observatory is run by the European Southern Observatory (ESO), and is so futuristic-looking that portions of the James Bond flick Quantum of Solace were filmed here. There's a hotel for scientists on-site, which looks like it is built underground; you'll enter the foliage-filled lobby as part of the tour. The observatory complex is situated on Cerro Paranal at 2664m above sea level, 120km south of Antofagasta; a lateral leaves the Panamericana just north of the Mano del Desierto (assuming you're heading south). The drive from Antofagasta takes about two hours.
The fascinating free visits are allowed on Saturdays, at 10am and 2pm. You must show up half an hour early; tours last two hours. You'll need to schedule months in advance (reservations are only accepted through the website), and you'll also need your own vehicle to get there. Check the observatory's website for details and updates.