It is super crowded. Would suggest buying tickets on line. Then once we got there, the very first thing we did was get in line for a 1 1/2 hour tram tour. You want to do it quick before the line is so long. They give you a riding tour. Stop and tour buildings, ride some more. It isn’t as droll as i am making it sound. It is super exciting. Learning how they came to put the space shuttle on a 747 (which you get to go in). 15 minute continuous reels of different titles. If you are going to get a soft drink, get those early. You can refill all day. Once you got inside, there is so much to see and do, it isn’t crowded like when you waiting outside to enter. Even the kids will enjoy. And it is an all day visit. If you go on tram, take bottle water with you. You cant take it in the buildings. But you sit in the same seat each time.