I've lived in Los Angeles, Seattle, D.C., New York, Las Vegas, San Diego, and Boston. I've spent time in Phoenix, San Francisco, Kansas City, Chicago, Miami, Portland, Atlanta, and Orlando. None of them come close to what you see in St. Louis. As a disclaimer, I always tell people, every bad thing you hear about St. Louis is true, and worse than you've heard -- but also that the many, many good things about St. Louis are never mentioned, and that's a shame. It's a long list and the City Museum is high on it.
But that said, check out this completely empty block on Delmar and 21st [1], and remember that with the Arch, that's less than 20 blocks from the river. And five blocks north of there is the former site of Pruitt Igoe, which is basically six or so blocks of wilderness behind a chain link fence. I don't doubt there are cities in worse shape (Detroit probably being one of them), but none that I've explored.
https://maps.app.goo.gl/ZWrwkK6CytcQRNmU6