When the first Protospacial Shunt was constructed between the Orion and Perseus arms of the galaxy it was nicknamed the Exchangeway because it promised to bring together two diverse sectors of interstellar culture. Wide enough to allow the passage of a small moon, the Exchangeway would forever change the galactic dynamic. No sooner had this transluminal conduit been carved from the stuff of spacetime that structures began to be constructed along its walls.
A millennium later, there are dozens of Shunts throughout the galaxy facilitating interaction between hundreds of races, but none possess the splendor of Longtown. Running the nearly 1000 light year length of the
Exchangeway it has become the largest city ever known. It rotates along the Exchangeway axis, with different zones rotating at different rates. The population is estimated in the tens of trillions. It has been said that the city can grow for another thousand years before it begins to get crowded, and even then plans are in the works to link all the existing Shunts into a vast connected network. Some wonder if the day will come when all sentient life abandons the galaxy to live within such structures.