End of 19th century: Leopold II decides to urbanize the Heysel plain composed of vast agricultural areas. He built up a vast estate of nearly 200 hectares through a policy of acquisitions and expropriations.
1926: In search of land on which to hold the festivities of the centennial of Belgian independence, the City of Brussels buys the Heysel Plateau from the royal family. The city had already planned to build a new exhibition complex of national and international dimensions, as the Parc du Cinquantenaire was considered too small.
1930: Construction of the 70,000 seat Stade du Centenaire [Centennial Stadium] (today Stade Roi Baudouin).
1935: Five halls are designed by the architect Joseph Van Neck for the Universal Exhibition. Fairs and exhibitions proliferate.
1958: The crisis of the 1930s and World War II made it impossible to divide Heysel into plots. The 1958 universal exhibition can thus occupy these grounds and avail itself of the existing infrastructure and facilities. Against a backdrop of an increase in the number of cars, the road network is recast. The Brussels Ring Road starts being built in the area close to the fairgrounds so as to channel traffic towards Expo 58. The general plan is now organized around the Atomium which is located in the centre of the site and ever so imposing for the entire site due to its sheer size. The exhibition centre was enlarged as a result.
1980s: The sporting and leisure dimensions are developed thanks to the presence of the Stade Roi Baudouin and the Brussels Expo Exhibition Halls s.