Very cool. You enter through TSA style security (e...

Very cool. You enter through TSA style security (empty pockets into a bin, walk through a metal detector) so be sure to factor that into your timing. You'll also want to buy your tickets in advance to be sure you can get a ride up. I once went with some folks who didn't realize this and we got there only to find the day was sold out. There are concessions, a gift shop, and a free museum in the base of the arch.

The trip up involves using narrow stairs to access the cars and top room. You also must be able to literally climb into these small cars which have little doors- it is definitely not accessible for folks with limited mobility and tall people will have a hard time fitting in. I'm about 5'7" and have to keep my neck bent a little to keep my head from hitting the ceiling. There are tour guides who tell some history about the arch and then send you on up.

Once you get to the top, you're allowed to stay as long as you'd like which is nice. There is air conditioning but be forewarned that it can be pretty hot, especially with all the people. I've never been outside of the summer but definitely suggest trying to go earlier in the day to avoid the heat. The top room feels sort of like being in an airplane without seats and it does get crowded. But the view is beautiful with windows on both sides and it's a unique experience. It definitely should be on any must-see list for StL.