Board Thread:Questions and Answers/@comment-33636382-20171113044643/@comment-26484417-20171113181048

The underground Tower is an idea that has been floating around the ToG forum for some time, though I don't remember who came up with it or where it first appeared.

The theory was born from the analogy between Shinsoo and water (Shinsoo density and pressure is stronger on the "higher numbered" Floors--very much like the water pressure grows as one dives deeper), as well as the fact that the Tower's door appeared below Rachel and Baam upon their entry (NOTE: I think this was the original building block of the theory.). In other words, the idea is that 1F is actually the closest to the outside world's surface, while the following Floors are stacked below it in order. As for the upside-down misalignment, that can simply be left as a property of the Tower; it's clearly a supernatural construct, so discrepancies of this magnitude aren't particularly unexpected.