The Ferris wheel designed by George Washington Gale Ferris, Jr. for the 1893 World's Columbian Exposition in Chicago. It was transported to the 1904 St Louis World's Fair grounds by rail, and demolished at the end of the fair. The whereabouts of the ginormous axle are unknown to this day.
Thomas Edison was head electrical supervisor of course
It's amazing to think that all of this was temporary, lasting only the duration of the fair