You might not know, but one of the rules set by the International Commission for Large Expositions stipulates that all pavilions built for the events should be dismantled after the end of the exposition in order to respect the provisional nature and exceptional aspect of the event itself. But the Parisian organizers have always been very crafty in dealing with this rule: for example, two of the major pavilions built shortly before the Universal Exposition of 1900 were not dismantled thanks to a simple trick where they claimed that the buildings had not been "specially built" for the event.
The two "pavilions" built for the Exposition are those still standing before you, the Grand Palais and the Petit Palais. The Eiffel Tower was another exposition construction that remained after the end of the 1889 Exposition, despite the great deal of controversy it aroused.
The Grand Palais and Petit Palais were erected opposite each other in a strategic position in the tree-lined space between the Champs Elysées and the new, wide Pont Alexandre III, which was also built for the 1900 Expo as a way to direct people's gaze towards the dome of the Invalides.
Keep in mind that the organization of the International Expositions themselves marked the 19th-century stages of technological and industrial progress, the evolution of artistic and architectural styles, and the affirmation of the major cities as reference points for the world. Every new Exposition was an opportunity to arrange immense new neighborhoods and introduce extraordinary innovations and spectacular installations capable of attracting millions of people.
For the great Universal Exposition of 1900 in particular, you should know that a revolutionary public lighting system and the first underground line were inaugurated, with the wonderful liberty signs designed by Hector Guimard.
FUN FACT: the Universal Exposition of the year 1900 lasted about eight months and had an amazing fifty million visitors. Among them was the great painter Henri de Toulouse-Lautrec, one of the protagonists of the Belle Époque, who was still young but already very ill and was pushed between the pavilions on a wheelchair. Another illustrious visitor was Marcel Proust, the perpetually cold-blooded novelist who wandered among the pavilions wearing two fur-lined coats, one on top of the other.
