BITD, I used to do a ton of building in the San Diego area. The known and developed climbing areas weren't quite as extensive as they are now, and my friends and I would look for anything to climb. This included splitter off-hand 10d / 11a cracks in the San Diego State University parking garage, the Bank of America building in Poway, some funky cement pours here and there around SD, etc.
The weird thing is, I'm still constantly scoping out buildering possibilities, even here in Seattle. There are some splitter 5.6ish cracks supporting the Alaska Way Viaduct, for instance.
My son has, through the years, said to me with regularity, "Dad, please get down!" as he looks around to see who's watching. I think that maybe climbers take longer to grow up than other people. Just a theory.
I was traversing a big stone building in St Petersburg, Russia once, and drew the attention of machinegun toting police.
BITD, as in CCCP, all I had to do was walk up to the front door of the
Communist Party Headquarters and start to take a picture of its beautiful
doors and the copper standing at the identical set of doors 50 meters away
came hauling azz down the sidewalk screaming,
Dude, they're just some doors! I'm glad I didn't try climbing on it.
Then I saw the unmarked car with the KGB goons in it. It was 0530.