The Atomium was built for the 1958 World's Fair and still today looks like something from a sci-fi movie. It is a combination permanent and temporary exhibits. The permanent exhibit is housed on the first two floors and is concept to creation of the structure. The temporary exhibit while we were there was Orange Dreams, which shows the creations of the 60s and 70s using plastics.
Going through the different levels is a combination of stairs and escalators through levels 1-6. For level 7, there were long lines for the elevator, the only way up or down, but they moved rather quickly.
Bonus, there was a waffle food truck just outside, which was a great little snack before we ate later in the evening.