Jurassic Animatronics from 1933
Computer generated dinosaurs are amazing on the big screen, but if you're building a museum display you want something even more alive and in your face. Disney elevated entertainment automatons to a high art in his theme parks in the 60's, but his "imagineers" weren't the first to create animatronic beasties.
Here's a full page scan of an article out of a 1930's issue of Popular Science. The accompanying text is woefully short, but it gives you an idea of the work that went into presenting prehistoric titans as realistically as possible at the Chicago World's Fair in 1933.
With all the tag sales I go to here in Chicago, I'm surprised I haven't found out who's garage these old mecha-dinosaurs ended up in.
Scan of original article [thanks to the Modern Mechanix archives]