Aside from the WikiLeaks mentioned by another poster, if you pull up your favorite AWS Region's city in Google Maps satellite view, you'll find the AWS facilities. It's the two or more long, narrow, white buildings with the roof entirely covered in AC units, generators in the parking lot, and a transmission switching station next to it. You'll find several clusters across the city; those are the availability zones. They'll have nondescript code names whereas all the other companies with data centers in the area have the company name labeled.

For example, here's an AWS facility in us-east-1. Pairs of narrow white buildings, ACs on top, generators in parking lot, switching station next door, nondescript name: looks like an AWS data center to me. (Thanks to the WikiLeaks doc I happen to know for sure this really is AWS, but you can tell just from the satellite.)

https://www.google.com/maps/@39.0271558,-77.4541392,698m/dat...

If you have the WikiLeaks document you can just google the "IAD50" type codes and generally find them, but that's no fun.