However, some of my relatives choose to live in or on the outskirts of large cities. Don't ask me why.
This guy has put a lot of thought into prepping in a big city, and I think he has some good points to make, especially on avoiding detection and the danger of fire:
Selco over at SHTF school writes about the subject, too. He was trapped in one of the cities in the Balkans. I can't read too much of what he writes in one sitting, because I saw some of it too. There are some stories that don't improve with retelling.