The only true structure in all of Hueco Mundo. A huge domed complex, the Espada and their subordinates reside here. Set up with various barracks and buildings, their original function lost with time. It is unknown who built it or if anyone else once lived in it.
The dark underground forest where most of the hollow population resides. Patrolled by the powerful menos, it is an extremely dangerous area where death could come at any turn. Only the fear of those that reside above keeps the other hollows hidden. The atmosphere is always heavy with fear.
The terrible landscape of Hueco Mundo is dominated by a huge desert. Very little resides in the desert save for a few weak hollows that would be killed in the Menos Forest, and a few strong Menos that do not fear the powers residing in Las Noches.
At the farthest northern edge of Hueco Mundo the desert fades away to be replaced by a black plain. Out of the interest and reach of the Espada, the few hollows that are able to survive the desert crossing are able to exist without the fear of the Menos or the powers in Las Noches and live in peace.