In the GE pavilion, the feature was a demonstration of nuclear fusion! So they said. We went into an area, and in the middle, there was a flash, and... fusion!
In the Borden pavilion, we got to meet Elsie the cow, in Person!
We also got the very first JFK 50 cent coins, mint condition!
Belgium introduced the US to the Belgian Waffle, I think it was a first.
Lots of other stuff, I was 12 and lived only a couple of miles away, so we went often.