Hueco Mundo (虚圏 (ウェコムンド), Wekomundo; Spanish for "Hollow World", Japanese for "Hollow Sphere") is the dimension in which Hollows and Arrancar usually reside. It lies in between the Living World/Earth and Soul Reaper World/Soul Society.
An unchanging night covers the sky, an endless white desert covers the ground. The tree-like objects are not plants, but rather quartz-like minerals.
The landscape of Hueco Mundo is a seemingly never-ending white desert, with a multitude of dunes, littered with boulders. In Hueco Mundo, the moon is on the opposite lunar phase of that in the Human World. The vast desert seems to lack any bodies of water and contains rocky formations. Like in Soul Society, the atmosphere is filled with a high concentration of Reishi, thus allowing smaller Hollows to gain nourishment despite the lack of Human souls.
Similar to the case of real world deserts, active life in Hueco Mundo appears to be few and far between. Hollows generally dwell below the surface or in other areas until something provokes them to leave their shelter, like the intrusion of a foreign entity. According to the Soul Reapers, all Hollows dwell in Hueco Mundo regardless of their shape, size, or power.
The world has no formal Government though they do have type of monarchy which is the strongest being in the world and is referred as King or Queen.
Economy, Social Class and CultureEdit
Is a Giant Palace like fortress that was formerly the base of Aizen's Army. Las Noches is an exceedingly large structure, appearing as large as (if not larger than) the Seireitei.
Forest of MenosEdit
There exists a vast forest underneath Hueco Mundo where Menos-class Hollows reside. The trees in this forest extend to the surface and dot the landscape above ground. The Adjuchas-class Menos which reside in this forest are under the control of Aizen.
Negal Ruins Edit
Is a never ending white desert that seems to cover majority of the world.