The Convention and the creation of the BIE marked a true change in the organization of Expos. However, 1928 was only the beginning of a long process led by the BIE of redefining, clarifying and specifying the characteristics of Expos and their regulation which the Convention had left open to the interpretation of countries.
After many previous amendments to the Convention, the amendment of 1988 was an important step in the history of the BIE. It clarified the difference between 2 types of Expos, General and Special, whose characteristics had been amended many times since 1928, and created World Expos and International Specialized Expos.
World Expos last up to 6 months, are not limited in size, participants can build their own pavilion, and the theme of the Expo has to be of universal concern.
Specialised Expos are limited to 25 ha, can last up to 3 months, are dedicated to a more specific theme and hosts provide participants with a space inside a pavilion. They were created to limit the organisation costs for hosts and participant countries.
In addition to these two Expos, the BIE also regulates the organisation of two other international Exhibitions whose characteristics match those of Expos in terms of international participation and duration: the Triennale di Milano regulated by the BIE since 1933 and Horticultural Expos co-organised with the International Association of Horticultural Producers since 1959.
Learn more about the 4 types of Expos.