Exhibit spaces are great to me when they have an awe-inspiring feeling to them, as well as an interactive component. An example I remember loving as a child was the Liberty Science Center in New Jersey. It has an observatory, IMAX theater, great view of NYC, and is loaded with scaled replicas of natural and constructed environments perfectly adjusted for kids to experience them and be excited. One pictured below with the crane operation in the lobby was one of my favorites.
Another exhibit I really like is a bit more informal. On the San Francisco side of the Golden Gate Bridge, there are plenty of information boards and interactive examples of the bridge’s construction. These are fun and extremely interesting, and give some perspective on the challenge that the bridge truly was.