Main Exhibition Building thumb|The main exhibition building; at 21½ acres, it was the largest building in world history at the time. thumb|The interior of the main exhibition building looking west from the grandstand The Centennial Commission turned to third-place winner's architect Henry Pettit and engineer Joseph M. Wilson for design and construction of the Main Exhibition Building. A temporary structure, the Main Building was the largest building in the world by area, enclosing . It measured in width and in length.
Main Exhibition Building thumb|The main exhibition building; at 21½ acres, it was the largest building in world history at the time. thumb|The interior of the main exhibition building looking west from the grandstand The Centennial Commission turned to third-place winner's architect Henry Pettit and engineer Joseph M. Wilson for design and construction of the Main Exhibition Building. A temporary structure, the Main Building was the largest building in the world by area, enclosing . It measured in width and in length