Cities are fake, an illusion, abnormal, phony, and artificial. Although they are centers of lots of population and activity, they can only exist at the expense of resources from elsewhere. Cities cannot make it on their own.
From a survival preparedness standpoint, cities are a big red flag, a place not to be when there has been a major disaster. Think about the dependencies. Food, water, electricity, and supplies are all trucked in from somewhere else. Although this is similarly the case for the suburbs and lesser so for rural areas, the fact that so much (of everything) has to be brought in to support such a large concentration of human beings is the Achilles heel.
I read this recently, “No city can feed its own people.” None of them. Cities are not self-sufficient. Not even close. Although most of us realize this, when you think seriously and logically about all of the dependencies that cities have today upon modern supplies and distribution, alarm bells begin going off in your head.
Cities depend upon farmers from the countryside and food sources that range from all over the world depending on season. Not only that, but the cities depend 100 percent on the distribution chains (trucking, trains, shipping) to deliver everything. If that was enough dependency for you, the cities only have about one week worth of food at any one time!
Not only do supplies need to come in, but trash and sewer needs to be brought out. These systems also have dependencies like trucking, electricity, and social order.
This is all invisible to the city dweller and is entirely taken for granted that the systems will not be disrupted.
Following a major collapse, the biggest and most immediate danger will be rioting and social chaos brought about by a lack of food, water, supplies, and money. If banking and electrical systems are out, cash money will be in short supply and will disable those who are scrambling to buy the last food and water off the shelves. The water demands for a city are enormous. When the water stops, it will be even more desperate than when the food runs out.
Imagine the modern buildings and apartment dwellings within the cities. Nearly all of them require an operating HVAC system (Heating, Ventilation, and Air Conditioning). Without it, temperatures will SOAR beyond bearable conditions in the summer and will PLUMMET in the winter. This will make it nearly impossible to live in them without electricity.
In a major disaster, this would all come about in days. Less than a week. Those who had failed to get out while they had a chance, will be doomed to very dangerous and difficult times indeed with their very survival at stake. There is even the risk that a city may become quarantined with all major routes in and out blocked (pandemic?).
Be aware that cities are death traps following major disaster. Your survival will depend upon having a plan BEFORE disaster strikes. Know multiple routes out of the city including routes that are NOT major routes. If collapse actually occurs, get out IMMEDIATELY. Better yet, stay out altogether. Or move.