Union is an extraplanar city which sits at the junction of many planes. It is a city of Celestials that was built above the Primordial Chasm to guard the approach to the Blessed Realm, the dwelling of the Valar. Union has been overrun by several times by transplanar armies many times. It changed hands during the Morgoth's First Darkness as much as seven times. It's last major capture was when a Heavenly Host captained by the Lesser Aesir Solaren expelled the occupying Elven army from the Empire of the Horizon. Solaren still rules the city and carefully guards its approach and access.
Points of Interest:
1) The Bifrost: Shimmering bridges of burning rainbow which bridge the Primordial Chasm and provide transport between various planes. Theoretically, this is a general term for for any transplanar bridge. However, unbridled celestials are known to skim or teleport through the AE the Celestial Spheres of the Ae and the Outer Darkness using similar phenomenon. Formally, the Bifrost are such bridges that creatures from Aetherea require in order to travel to interplanar locations such as Union. There are two major bridges which can link the city of Union to other planes. One connects Union to the City of Rosen. The other connects Union to the Blessed Realm, the dwelling of the Valar.
2) The Crux: The Crux is a luminescent sphere which is the exact intersection of all planes within the AE. It is a place where the laws of all planes merge into one Universal Law. Celestials believe that this is the original point of creation where Illuvatar spoke the AE into existance, so they guard it with the utmost reverence. This was also the point that the Valar and all of their followers entered the AE in order to take command of creation. The Crux is composed of a uniquely pure aethereal substance called Purity. It is the most potent substance within the AE. Starsmiths among the Celestial Company use this substance to craft the Sun and the stars.
3) The Hall of Doors: When the King of the Valar, Manwe commanded the Celestial Company to construct Union, he left them a blueprint four mysterious complex known as the Hall of Doors. The exact purpose and function of this complex is unknown to even the Celestials. However, it appears as an endless, winding, ever-changing and confusing hall filled with endless stairs, doors, windows, frames, and halls. These all serve as portals for which (it seems) any point in the AE may be randomly accessed. At the center of this complex is the Crux.
4) The Portcullis: The Portullis is a massive gate, forged from Celestial blood and Purity which bars the way to the Blessed Realm. It is said that only two people possess its key whom do not live in the Blessed Realm; Solaren and Helios. Solaren the Lesser Aesir who rules Union and Commands its Heavenly Host. Helios is the Greater Aesir who drives the Chariot of the Sun. He must access this gate once per day in order to rejuvenate within the Blessed Realm.
5) The Mausoleum: The Mausoleum is a high vaulted sanctuary which houses the tombs of all Celestials which have laid down their lives in the defense of the AE. Not all Celestials who have perished are interred here, for many are burried within Aetherea or lost to the Outer Darkness. However, all are represented with a tomb. This is considered one of the most holy places within the AE outside of the Blessed Realm itself. Many extaplanar pilgrims seek out this place in order to obtain freedom from difficult curses, etc.
