I would choose a tunable LED light fixture display with RGB capable programming, along with a controller to dim and adjust the light color temperature. The 1893 worlds fair that was powered by Tesla and Westinghouse would have a fit.
IF YOU COULD TAKE ONE THING BACK IN TIME TO A WORLDS FAIR TO SHOW THE WORLD HOW FAR WE'VE COME; WHAT WOULD IT BE AND WHY? EVERYONE IS GOING TO SAY CELL PHONES, SO TRY TO BE ORIGINAL