I recommend reading "The Devil in the White City" by Erik Larsen. Although it's centered around the exploits of H.H. Holmes, a serial killer, the book also goes into great depth about the 1893 World's Fair, which introduced the Ferris Wheel (meant to be America's response to the Eiffel Tower marvel), the introduction of Juicy Fruit gum sticks and Cream of Wheat, and one of Thomas Edison's last ditch efforts to popularize his DC current format in the U.S. by powering an "electricity building" attraction.

A similar question, 'Why did world fairs stop being a big thing?' was asked here: https://www.reddit.com/r/AskHistorians/comments/3nc9nb/why_did_world_fairs_stop_being_a_big_things/

The short summary of /u/GravitasIsOverrated and /u/MrDowntown's posts is that the fairs still happen, but they're more distributed (occurring around the world rather than just in the western world) and many industries split off to host their own trade shows and conventions over the years.

The phrase "World Fair" is the name commonly given to events called Universal Expositions. These Universal Expositions are today generally understood to be events organized by the Bureau International des Expositions, where companies, associations, and other groups of people exhibit their achievements, however big events calling themselves "World Fair," "Universal Exposition," or some variation thereof have also been organized independently. Almost always, individual delegations will stage a number of exhibitions in specially constructed pavilions on an established exhibition ground, exhibitors are often grouped under a single national umbrella and sometimes adhere to a single common theme, which may or may not be tied to a theme given to the entire fair.

The "Gold Standard" of Universal Expositions is the one held in Paris in 1889. In his travelogue "Innocents Abroad," Mark Twain narrates how he and some friends use the pretext of visiting the Exposition to go on an extended holiday in Europe. It must have seemed like almost all Americans of some means were visiting Paris in 1889, as in his book Twain even recounts how an absent-minded man attempted to settle a debt at a store with the phrase, "I'll pay you back when I see you in Paris," seeing as "...when I see you in Paris" had seemingly (Twain jokes) become the most common way to end a conversation.

In a world without internet, television, or telephones, many people had to wait years before they could see firsthand the kinds of inventions they read about in newspapers, in addition to all a manner of things that might not have been reported in their local paper. In fact World Fairs allowed people to see things they had never seen before, and much more: as World Fair exhibitors attempts to out-do each other by constructing elaborate pavilions and showing off their best national products as well as latest innovations, these events were also opportunities to learn about new cultures. Hosting the World's Fair was comparable to hosting the closest thing to the Internet for a year.

Paris, the shining epicenter of the Belle Epoque, was an understandably popular location for these fairs. The Eiffel Tower, the most iconic symbol of Paris and France, was built as a stunt for the 1889 World's Fair!

Cities in the United States, a large and sometimes isolated country, also played host to a number of very successful World Fairs. The World Fairs were also ways for countries to increase their international prestige: Paris hosted four to demonstrate France had recovered from the Franco-Prussian war, while Italy hosted one in Milan to prove that after unification, it had come into its own as an industrial power (you can see some archival photos and read more about it —in Italian— here). Italy was also due to host another World's Fair in 1942, in a purpose-built neighborhood south of Rome. Although the Fair was never held due to the outbreak of the Second World War, the neighborhood is still in existence and in use as a business park.

Even in the information age, World Fairs continued to be relevant. In 1964, New York staged one in Flushing Meadows, Queens. You might have seen weird flying-saucer like structures when driving from La Guardia Airport to Manhattan; those were once part of the fairground, and other structures built for the fair now decorate Flushing Meadows Park. The fair, financed in great part by businessmen who fondly remembered the 1939 New York Fair, was a showcase of the achievements of American manufacturers in the space age.

Nowadays, news travels very fast, and we don't need to travel to a World Fair to see the latest technology. However, this hasn't stopped fairs from being staged. More recently, Universal Expositions have been used to re-launch and redevelop cities as well and mark the start of large public and private construction projects. In 1992, for example, the Spanish government staged a Universal Exposition in Seville to mark 500 years since Columbus' voyage. The Exposition yielded a flurry of public and private construction and redevelopment.