Outside

"Outside the Tower, there exists a vast world, rolling skies stretch endlessly, and countless stars illuminate the darkness. A place that is a thousand times -- no, a billion times wider and freer than the Tower."

- Urek Mazino describing the world outside the Tower."

The Tower resembles a world unto itself; each Floor is a massive, continent-sized culture over which Guardians and Rankers rule. The vast majority of inhabitants are born within the Tower and the vast majority will die there, never knowing another world exists. Yet according to Urek Mazino, the Tower is tiny place compared to the world outside. Little is known about this outside world, even Irregulars who entered the Tower do not know how to leave.

About
In Of the Tower's Weapons, Ashul Edwaru states: "...there's no Shinsoo in their world and something called 'air' fills their world instead". He also writes that all the weapons used in the Tower are modelled after weapons from outside the Tower, which were brought in by Zahard and the 10 Great Warriors when they entered from the outside.

Urek Mazino describes the Outside as a vast and open world, full of rolling skies and stars. Similarly, when speaking to Baam immediately before entering the Tower, Rachel said: "If you climb the Tower, you'll be able to go outside... you can see a blue sky during the day and a starry sky during the night". Urek Mazino, who entered the Tower tracking Phantaminum, now seeks a way to leave the Tower. Inspired by the many tales told by Urek Mazino, Wolhaiksong seeks the same goal, though none of them ever succeeded.

According to the Great Father Macseth, the Gong Bang, also exists outside of the Tower; it's unknown how Macseth can know this.