It was above all Expo.02's giant walk-through cloud which caught the attention of the international press.
"Ethereal and compelling...the Cloud is the star of Switzerland's costly, controversial and imaginative national exhibition," wrote Britain's "Guardian".
The Cloud, designed by New York architects Elizabeth Diller and Ricardo Scofidio, was the star attraction at the Expo arteplage in Yverdon, one of the four national exhibition sites in western Switzerland.
The paper described the Cloud as "the kind of structure all too often missing from international expos".
"It is a work that points the way to new forms of buildings... that are made of the latest materials but are still a recognisable part of the natural world."
Britain's "Economist" newspaper also singled out the artificial cloud for praise, describing the experience as both "disorienting and liberating". The writer felt like he was "walking into a poem - it is part of nature but removed from reality".
The cloud was the only thing at Expo.02 that took the Economist's fancy - it advised visitors to skip the rest of the show, dismissing it "a Swiss kitsch version of Britain's Millennium Dome".
The London-based "Independent" newspaper praised exhibition organisers for abandoning traditional, clichéd images of Switzerland in favour of "New Agey (sic) journeys of self-discovery".
"Expo.02 features no model of the Matterhorn, no cuckoo clocks, no Swiss cheese. Instead there is a huge, damp artificial cloud; Pink Floyd music; and Swiss francs being shredded by a robot".
In its review of the event - the first such national exhibition in Switzerland since 1964 - the "New York Times" focused its attention on the way Expo.02 sought to encourage a debate about national identity.
Expo.02, the paper wrote, provided "a healthy dollop of societal bonding, necessary in a country with four languages and three cultures".