A: The first World Expo held in London in 1851 did not have any theme, and the expos that followed served as just as exhibition centers for new products untill the 1933 Chicago World Expo initially introduced the conception of "theme" and took on "A Century of Progress", demonstrating that technological creations and innovations would be the driving force for social progress and development. Ever since, world expos have attached great importance to exploration for human civilization, technology and arts.
