<human>: Before you read any of this, please refrain from comments like "Well obviously not, you're retarded." or "Are you actually serious?" I'm just curious what is considered a building.

Are twin towers, such as the [Petronas Towers] a single building? They're attached together, and share a foundation. If you say they are a single building then proceed. If you disagree, I suggest you stop here.

Vancouvers [Skytrain] [Link isn't working, add a ")" at the end of it] system is "running mostly on elevated guideways" and the elevated guideways are independently standing. They connect all of the Skytrain Stations. By the same logic as before the whole system is one large structure. If you agree, proceed, if not, halt.

Many of the stations are built so one can have easy access to the major center they're near. [Metrotown] [Waterfront Station] and [Pacific Center] are good examples of this, being directly built into another building or having walkways built to connect them together. This effectively attaches them together, arguably making them one unified structure. If you can accept this, then please continue on. If not, I urge you to stop and not risk being provoked.

So if all the stations built into/attached to other buildings/malls/etc being unified structures and all the stations, via elevated guideways, are one unified structures, does that make all them together one whole structure? If so, is it one [incredibly large and spread out building] 

Aside from that question, what is a building to you guys? What is the most simplest structure that can be defined as a building and is there a certain level of complexity it can reach making it no longer classified as a building?

Summarize the given text in a few sentences.
<bot>: What makes a building a building? And could a skytain transit system connected to multiple malls/complexes be considered a building?