There's an exchange building in Queens, New York, that looks (from the sidewalk) like an Aztec pyramid. It's actually the base of a much larger building that was never finished. They built a little, and realized that they didn't need any more space because the switches were a lot smaller than when the building was planned.
If you google "queens center mall" it's across the street on the other side of Queens Blvd. It has buttresses that look weird because they aren't holding up anything.