When CERN opened its doors to the public for its open day on 16 October, the laboratory took on the air of a county fair. Children took rides around the site in a big lorry, visitors ate ice cream that had been handmade in a flash using liquid nitrogen, and crowds strolled the lanes as they visited more than 50 events across various sites in Switzerland and France.

An estimated 32,000 visitors, from across Europe and beyond, flocked to the laboratory for a day of tours, displays and presentations. The majority of events were in experiment halls and workshops that are normally closed to the public. The last open day was in 1998, and this one attracted so many people that visitors had to wait in long lines at the main events.

Some of the biggest attractions were the huge detectors under construction for the Large Hadron Collider. Such tours helped the visitors gain a sense of the scale of CERN's work - and even those who already had some notion of CERN were awed by the gigantic detectors, caverns, and tunnels.

Some of the attractions gave visitors a more direct feel for the science and technology behind research at CERN. In one hall, volunteers revealed the strange properties of matter at low temperatures with a miniature train levitated by a superconducting magnet, and demonstrated superfluidity in liquid helium. At the GridCafé, visitors could surf the Web and learn about the networks of computer centres that CERN is helping to organize. At another site, visitors gained hands-on experience assembling their own working cosmic-ray detectors.