Bah, too slow on edit, I missed post #82.
Isn’t San Diego a well known city by you?
(Of course, whether San Diego is the real world could be debatable…)
Or you’re a super villian intent on mayhem and destruction. You even made a laser to give Manhattan a fault line.
Yet weep when just the WTC falls down.
Never, ever ask yourself, “What if…” It’ll never work our in your, or anyone else’s benefit.
Coast City, though it’s slowly coming back.
Pittsburgh never got better, though of course the book got cancelled.
Metropolis and Gotham both got reduced to rubble for quite some time. Well, story-externally quite some time. Story-internal, Metropolis was back within three months, but hey, they’ve got Zatanna.
On top of vast portions of San Diego becoming Sub Diego, and Pittsburgh getting wiped out, Vandal Savage nuked Montevideo, Uruguay a few years back (The city of Superbia now floats above where Montevideo used to be - unless it’s been retconned).
Of course, a lot of Sub Diego resurfaced according to the latest Aquaman, but there’s still portions underwater, and the resurfaced portions are probably still not particularly inhabitable, and won’t be for some time. And Sub Diego included several major portions of San Diego - the zoo, off the top of my head, was one of the areas to get submerged.
(Also, since ‘real world’ only applies to cities and landmarks, in 52, Black Adam recently decimated Bialya, which is a fairly major (if fictional) country within the DCU.)
None of those are real world cities, though.
I’m not sure you can count Pittsburgh as a counter to Der Trihs’ point. The books and universe in which that happened were already dying by the time the decision was made to kill off Pittsburgh and make the changes permanent in the whole New Universe. At which point it’s more another What If…? than any real effect on a comics continuity.
(Yeah, the New Universe limped on for another… ~10 months, and then a few other ‘bookcase’ format titles, after The Pitt, but the handwriting was on the wall, even before The Pitt.)
Don’t bother me with facts. 
Can I take this time to mention how cool you are just to have read and remembered that 20 year old experiment?
(No, some of those titles couldn’t possibly have been some of my favorite comics titles. Not at all.)
If I tell you I have every New Universe issue published, how much will you hate me?
Not at all. I ended up with most of them, myself - never did get Nightwalker #1, but never was all that desperate for it, either. Sorry, you’re still cool, and you can’t make me hate you.
But I might want to look at your books sometime. 