Towering above the vast deserts of Heuco Mundo's equivalent to the Chihuahuan Desert is the vast palace known as Las Noches. With a diameter of two-hundred kilometers, this superstructure covers as much land as Seireitei does in Soul Society, with halls and chambers of a sort more grand than any ever found on Earth. Las Noches is considered the capital of Heuco Mundo, the center of the dimension, where those Menos and Arrancar willing to assemble together form an alliance against their mutual enemies, the Shinigami and the Quincy.
Las Noches Throne
In the center of the dome of Las Noches rests the Las Noches Throne, where the King of Heuco Mundo resides. This king always has been, and is expected to be a Menos of the Vasto Lorde class, although there is a chance an Arrancar of the same power could overthrow the king and break tradition. Within Las Noches, the King's word is law, though Menos are a diverse lot, and there are as many fully independent Menos that stay the hell away from Las Noches as there are Menos faithful to the Throne and the king who rules over Las Noches. Arrancar, on the other hand, are a little different. The shinigami nature that filters in from the breaking of their masks tends to curb their independent streaks, and give them a desire for order. (Not all Arrancar submit to Las Noches of course, but a strong majority do.) Among those loyal to Las Noches, the twelve strongest are chosen for Espada.
There are only two things that Menos respect, strength and cunning. In order to hold the throne of Las Noches, or an Espada position, requires both in great supply. In Las Noches, the strong quickly rise to the top, while the weak are pushed under the feat of their betters. Due to threats Hollows face, killing each other within Las Noches walls is expressly forbidden. Outside Las Noches is another story entirely, however, with rivals frequently devouring one another; to both free themselves of a rival and grow stronger, and position themselves better in the Las Noches hierarchy.