Expo 58, also known as the 1958 Brussels World's Fair (, ), was a world's fair held on the Heysel/Heizel Plateau in Brussels, Belgium, from 17 April to 19 October 1958. It was the first major world's fair registered under the Bureau International des Expositions (BIE) after World War II. Background Expo 58 was the eleventh world's fair hosted by Belgium, and the fifth in Brussels, following the fairs in 1888, 1897, 1910 and 1935. In 1953, Belgium won the bid for the next world's fair, winning out over other European capitals such as Paris and London. Nearly 15,000 workers spent three years building the site on the Heysel/Heizel Plateau, north-west of central Brussels. Many of the buildings were re-used from the 1935 World's Fair, which had been held on the same site. The theme of Expo 58 was "Bilan du monde, pour un monde plus humain" (in English: "Evaluation of the world for a more humane world"), a motto inspired by faith in technical and scientific progress, as well as post-war debates over the ethical use of atomic power. The exhibition attracted some 41.5 million visitors, making Expo 58 the second largest World's Fair after the 1900 Exposition Universelle et Internationale de Paris, which had attracted 48 million visitors. Every 25 years starting in 1855, Belgium had staged large national events to celebrate its national independence following the Belgian Revolution of 1830. However, the Belgian Government under Prime Minister Achille Van Acker decided to forego celebrations in 1955 to have additional funding for the 1958 Expo. Since Expo 58, Belgium has not organised any more world's fairs. Exhibition More than forty nations took part in Expo 58, with more than forty-five national pavilions, not including those of the Belgian Congo and Belgium itself. The site is best known for the Atomium, a giant model of a unit cell of an iron crystal (each sphere representing an atom). More than 41 million visitors visited the site, which was opened with a call for world peace and social and economic progress, issued by King Baudouin I. Notable exhibitions include the Philips Pavilion, where "Poème électronique", commissioned specifically for the location, was played back from 425 loudspeakers, placed at specific points as designed by Iannis Xenakis, and Le Corbusier. Belgian Congo Section The Belgian Congo section was located in in close proximity to the Atomium model. The Belgian Congo, today known as