For what it's worth, the Spivey Building is almost 100 years old and it's been abandoned since the '50s.

https://en.wikipedia.org/wiki/Spivey_Building

St. Louis has a lot of cool abandoned architecture, although you might want to be careful wandering around East of the river.

I wonder how many cities have abandoned towers that became historical places thanks to longstanding traditions of not being able to afford a demolition.