The Japanese prefecture of Aichi was declared the host of Expo 2005 by the General Assembly of the Bureau International des Expositions in June 1997, surpassing the bids of Calgary, Canada, and Gold Coast, Australia.

On December 15, 2000, at the 128th General Assembly of the Bureau International des Expositions, Expo 2005 Aichi was registered under the official name of “The 2005 World Exposition, Aichi, Japan” with the theme “Nature's Wisdom” and subthemes “The Matrix of Nature,” “The Art of Life,” and “Development for Eco-communities.”

At the time of the candidacy's registration, the 1988 amendment had not yet come into force, and therefore, the categories International Registered Exposition and International Recognized Exposition did not exist, only the categories Universal Exposition and Specialized Exposition established by the 1972 amendment. For this reason, contrary to what various sources claim, Expo 2005 Aichi was not a Universal Exposition nor a Registered Exposition, but a Specialized Exposition.

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Expo 2005 Aichi remained open to the public for 185 continuous days, from March 25 to September 25, 2005, receiving, according to official figures, 22,049,544 visitors. The number of visitors per day ranged from a minimum of 43,023 on March 25, the opening day, to a maximum of 281,441 people on September 18.

In addition to Japan, 121 countries and four international organizations participated, grouped in 69 pavilions. The site area covered approximately 173 ha spread across the Eastern Hills of Nagoya, between Nagakute and the cities of Toyota and Seto, in the Aichi Prefecture.

Media coverage was provided by approximately 1,800 journalists, sent by 380 press organizations from about 75 countries.