When you talk about going "Back to the Fairs," you can't go any farther than the Great Exhibition of 1851 - otherwise known as the first World's Fair. While nothing really remains from the Fair, every time I visit London, I always make a trip to Hyde Park where the Fair was hosted - retracing the steps of the first World Expo and remembering where it all started.
The Great Exhibition of 1851 was created by Prince Albert & Henry Cole, aiming to create an event that brought tougher people from All Nations to show their latest goods and "to educate the populace about the value of industry and commerce." A contest was held to design a building to host the countries from around the world, which was eventually won by Joseph Paxton, who designed the "Crystal Palace." While the Crystal Palace was moved after the Expo ended, and eventually destroyed by a fire in 1936, there are now signs and plaques across Hyde Park, where the Crystal Palace originally stood.
In 2011, 5 plaques were installed on the floor to commentate the Great Exhibition of 1851. Four of the plaques have quick facts about the Exhibition and are at each of the four corners of the original Crystal Palace. The fifth plaque marks the entrance of the Expo.