The Palais Wilson was used until 1936 as the main building of the League. However, from 1920 to 1929, the Assembly met in Geneva at the Salle de la Réformation (in a building at the corner of Boulevard Helvétique and Rue du Rhône), then from 1930 to 1936 at the Bâtiment électoral or Palais Électoral (Rue du Général-Dufour 24, later used by the Red Cross affiliated International Prisoners-of-War Agency). For special sessions, the Assembly met at the Pavillon du désarmement adjacent to the Palais Wilson.[3] In 1937, the Assembly moved into the Assembly Hall of the Palace of Nations.
An architectural competition held in the 1920s to choose a design for the complex described the project as follows:
The Palace, whose construction is the object of the competition, is intended to house all the organs of the League of Nations in Geneva. It should be designed in such a way as to allow these organs to work, to preside and to hold discussions, independently and easily in the calm atmosphere which should prevail when dealing with problems of an international dimension.
A jury of nine architects was selected to choose a final design from among 377 entries: Hendrik Petrus Berlage, Victor Horta, Josef Hoffman, Charles Lemaresquier, John James Burnet, Attilio Muggia, Ivar Tengbom, Carlos Gato of Madrid, and Karl Moser.[4] The jury was unable to choose a single winner.[5] Ultimately, the five architects behind the leading entries were chosen to collaborate on a final design: Julien Flegenheimer of Switzerland, Camille Lefèvre and Henri-Paul Nénot of France, Carlo Broggi of Italy and József Vágó of Hungary. Donations from League members were used in the interior.
The Palace constituted at the time of completion (1936), volume wise, the second-largest building complex in Europe after Versailles (440,000 m3 (15,500,000 cu ft) vs. 460,000 m3 (16,200,000 cu ft)).[6]
After its transfer to the United Nations, two extensions were added to the building, which considerably increased the size of the usable area of the building. Between 1950 and 1952, three floors were added to the "K" building, and the "D" building was constructed to house temporarily the World Health Organization. The "E" building (or "New" Building) was added between 1968 and 1973 as a conference facility (an additional eleven conference rooms and an extra volume of 380,000 m3 (13,400,000 cu ft)), bringing the total number of conference rooms to 34. With the additions, the complex is 600 metres (2,000 ft) long and holds 2,800 offices, with a total volume of 853,000 m3 (30,100,000 cu ft)[7]
The Palace is located in Ariana Park, which was bequeathed to the City of Geneva in 1890 by Gustave de Revilliod de la Rive [fr; de], on two conditions: i.e., that the park always remain accessible to the public and that he be buried in the park. The park also contains a 1668 chalet.
Beneath the Palace's foundation stone is a time capsule containing a document listing the names of the League of Nations member states, a copy of the Covenant of the League, and specimen coins of all the countries represented at the league's Tenth Assembly. A medal showing the Palace of Nations with the Jura Mountains in the background was struck in silvered bronze.[9]
^Pallas, Jean-Claude (2001). Histoire et architecture du Palais des Nations (1924–2001): l'Art déco au service des relations internationales (in French). Geneva: United Nations. pp. 100 and 104. ISBN978-9-2120-0354-2.
^Petite, Simon (23 December 2013). "Rénovation du Palais des Nations: vote crucial". Le Temps (in French). Geneva. p. 5.