see it first here

exhibition is also a place to launch innovations to public.

Here is the first Ferris wheel from the 1893 World Columbian Exposition in Chicago. Not only this sort of inventions are to introduced in an exhibition, achievements in science such as current electric, turbine engines, or permanent buildings like the Tour Eiffel in Paris were firstly shown in the occasion of the great exhibitions. These first things exhibited were not all be immediately acclaimed or proved to last but they were launched in exhibition so as to 'test' something. Tour Eiffel was much hated then but when many years past now it becomes the pride of Paris.