I'm British and my first trip to the States was to Chicago in 1998. I remember my first taste of Chicago-style pizza, there were 4 of us going to the restaurant and they were talking of just ordering 1 12" pizza, I was saying "we need more than that" and they said, "no you won't, you'll only be able to eat 2 or 3 slices" and I was thinking "I thought American's ate loads, I can eat a 12" pizza myself!"
Anyway, when the deep-dish pizza arrived I realised what they meant! I love them, and like to go to Cafe Uno's when we go to NJ, there was one next to our hotel last year.
Well, not long after I got home I saw "Chicago Town pizza" in the freezer and just laughed......it's so far away from a Chicago pizza it's untrue!