The space city diametrically opposed to Ketheres.
It pumps oxygen and seawater from the surface via the orbital elevator for export to the colonies.
The corresponding surface gate city is Nezher.
[Mentioned in Last Order, volume 3, Angel Eternal, page 80]
According to Wikipedia (edited):
Binah, (Hebrew for understanding), in the Kabbalah of Judaism, is the second intellectual Sephirah on the tree of life. It sits on the level below Keter (in the formulations that include that Sephirah), across from Chokmah and directly above Gevurah. It is usually given four paths: to Keter, Chokmah, Gevurah, and Tiphereth (some Kabbalists place a path from Binah to Chesed as well.) In an anthropomorphic visualization, it may be alternatively related to the left eye, left hemisphere of the brain or the heart.
Binah is processed wisdom, also known as deductive reasoning. It is davar mitoch davar — understanding one idea from another idea. While Chokmah is intellect that does not emanate from the rational process; it is either inspired or taught. Binah is the rational process that is innate in the person which works to develop an idea fully.