I am currently visiting the USA, and before I leave I want to try some food that is "uniquely" american - IE, you can't really find it outside of the country.
UK stores do tend to have a "USA section" which has a small amount of sweets and other products. But I am wondering what americans specifically missed / couldn't find in other countries.
As an example - Wendy's as far as I've seen, isn't local to the UK or at least where I live. So trying that was a "unique american food", to me.
I'm also in Chicago at the moment, so I made sure to try a proper (real?) Chicago deep dish pizza (loved it, by the way).
Alternatively, any other suggestions of food to try?
Immediate edit - turns out Wendy's is in some locations in the UK. I just assumed incorrectly!
Thanks for all the suggestions!!
Since you're in Chicago, I suggest finding a restaurant called Au Cheval and getting a burger.
It's been a few years, but it was one of the best burgers I've ever had.
As far as food you won't find much of in the UK, I agree with other commenters to find good Tex Mex and a good diner.
Tex Mex is better in Texas, but Chicago is a major city with great food, so I'd be surprised if they don't have great Tex Mex somewhere. You could also look for a taco truck. Actually, look for food trucks in general. I don't know if the UK got that same amazing food truck fad that the US did a few years back, but you should be able to find a park where a bunch of food trucks gather and you can try a little of everything. (If you find one with Venezuelan food, do not pass it up.)
For a diner, you're looking for something a little more run down, not a chain, and probably off a highway rather than in the main part of the city. It should be open 24 hours and serve breakfast all day. Look for reviews that seem way better than how the building looks. Again, Chicago probably isn't the best spot for it (that'd be upstate New York and New Jersey), but there's bound to be something.
I don't think we got it to the same extent, but it definitely reached us. However given how we're a long way from Latin America and have fairly few immigrants from there, we tend to have other cuisines in them. Indian in particular (which I'm absolutely not about to turn down).
There's a fun not-quite-a-truck "food truck" set up in an old tram car in the centre of the nearest city to me. The guy that runs it does good stovies.