"Good evening wasteland. Mr. Hobbes is feeling a bit ill today, so I'll be taking over. Please excuse the lack of Wolfman Jack impressions.
So, there have been some more questions about NEST structures. Most specifically, how do you break into one? What is inside? Is it worth the effort? If not a NEST, where else?
I need to preface this by saying, neither I nor Mr. Hobbes have been inside one of these structures. Only one or two people we have spoken with have been in, or even near these super towers. Most of the units in the system were either quickly sealed and thus continue to host a population dedicated to fiercely defending them, or quickly hit a critical mass of reanimates, and no longer contain anything alive. Entrance is unlikely.
NEST structures are quite like flakturm. These the giant reinforced concrete anti-aircraft bunkers and air raid shelters built around Germany in the second world war were so tough, that not only did they survive allied bombing, point blank Soviet heavy artillery couldn't scratch them, and after the war, conventional demolition techniques didn't work either. Some were simply buried under the rubble, others continue to stand. I would not be surprised to learn people have started living in them again.
This is where I would complain in his headphones that Mr. Hobbes is off topic, and in turn, he would say it is an educational service. I am not as fast paced as my employer, but I do have some humor.
So given that they are made of extra-tough materials and designed to be locked down to contain emergencies, how do you get in? Well, first of all - you can try the doors. Think a shopping mall or stadium - there needs to be some way to let thousands of people in and out in a reasonable amount of time. The bottom level is often set up like a strip mall on the outside, so there are individual shops where the employee back door has been missed and left unlocked. Or perhaps the entrance was smashed by previous looters, and if you have picked up the rather useful skill of bypassing locks - well, good for you.
Failing the most obvious, the next trick would be one that applies to most multi-story structures. Stand back and find a way to shoot out a window on the second or preferably third story. A ground floor forced entryway will let reanimates and such walk right in - but only a few can climb or jump seven meters.
Few people realize how far the basement of these things really goes. There are probably an extra ten or twenty stories going beneath the structure. If you can find a subway entrance a few kilometers away and make your way through the monster infested underground, you will find yourself in a terminal, and bypassing normal security is an exorcise left to your own discretion.
Another underground possibility is getting in through the grates that cover one of the hydrological systems. At the very least, they have a sewage treatment system, and probably another inlet for drinking water. Heavy machinery like pumps, high-speed elevators, and power generators need coolant - so that may be another inlet.
For those with access to the exotic - a helicopter flown to one of the various helipads is an option. There are usually a minimum of eight heliports - to accommodate landing from various directions - and because there used to be a large amount of air traffic. After-all, they hosted police, fire, medical, and military facilities, all of which used helicopters on a daily basis.
Once inside - well, I don't know how many times this needs to be said - they are a city in a bottle. Whatever you could want is either there, or was there but was looted by a better scavenger than yourself.
You will find an all you can eat buffet of reanimated. And then some. Tons of rats, birds and bats are also rather likely, along with other vermin chewing the electrical and helping themselves to forgotten food stocks. In turn, those are probably preyed upon by the escaped pets of the former inhabitants, maybe some birds of prey in the larger atrium. Given time, these places will become ecosystems unto themselves. But for now you will probably only worry about vicious German shepherds and insect borne diseases - not something evolved specifically for hunting in a super tower.
I would imagine many of our listeners are quite unwilling to take a hundred plus story dungeon crawl lightly. There are a few options,as the Economical Design and Governance Enclosures. An edge - colloquially known as a "NEST Egg" is a similar idea, but on a much smaller scale in an attempt to avoid the massive costs, time commitment, and logistics of making a NEST.
Unlike the NESTs, there are somewhat more hap-hazard. Many were designed in blocks and for adding on as necessary. Some are one structure akin to a large stadium with outliers, and others are more like underground complexes with a few domes on top for agriculture. Population could be as low as three thousand, to perhaps ten times that. Generally speaking, megastructure arcologies were built near the coasts and between major cities to alleviate urban sprawl and take advantage of existing infrastructure. Edges are more likely in places with less capacity to transport materials, farther inland - or in parts of the West Coast where the massive supply chain for NEST building would have crippled the city's services. That is why there is no Los Angles arcology for example.
Unfortunately, we are out of time, and will have to explore this again later. Good night and good luck in the zone.