Hey, I lived in St. Louis for 3 years - west end of Forest Park, near the University City gates. A couple blocks off of Delmar, if that rings a bell, near Skinker.
The Arch is definitely cool. When I worked in STL my desk was in a 7th floor corner a block away, looking straight over the Old Cathedral through the Arch. Beats the heck out of my current view.
Cosmic
Damn , that's high
While I was there, one guy got killed trying to base jump off the top of it. He parachuted from a plane to land on top of the outside part of the Arch (the roof over the room in LM's second pic). He had a second chute in another pack, and he was going to jettison the first one after landing and make the base jump using the second one. But the wind wrapped the first chute around the top of the arch before he could shrug it off, and whipped him down to the ground.
The next summer, another guy did it using a better plan. He snuck down in the middle of the night and spent about 3 hours climbing up from the ground using suction-cup wallwalkers on arms and legs. He got to the top and took a nap up where nobody could see him. Then, about 10:00 in the morning, he stood up with a big American flag, waved it for a minute, and jumped off with his drogue chute. I missed his actual jumpoff but I saw him come down sucessfully after the canopy opened, and I watched him get busted by security minutes later... but at least he didn't die.