Gate-town

A gate-town, or portal town was a village or town on the Outlands built around a gate leading to one of the other Outer Planes.

Description
Each portal town was a mimic of the plane to which its gate led. A gate-town bordering an evil plane would likely have inhabitants hostile to good visitors, and a town bordering a lawful plane was likely to be very organized and orderly. This "mimicry" applied to the region around the gate-town as well, so that the landscape for miles around the town of Xaos might be a mess of tangled bushes and overgrown grass.

The gate-towns were equally spaced from each other and sat about  from the spire at the center of the Outlands. While one would think to be able to use simple geometry to calculate their distance from each other, the strange and mutable nature of the Outlands meant that the nearest gate-town took between and  of travel to reach, no matter where one had actually started relative to the spire.

Thus, while the Outlands were said to be infinite, it was effectively impossible to travel in a meaningful way more than from the spire, and the ring of portal towns thus acted as a sort of border of the Outlands.

Moving clockwise around the spire, the sixteen gate-towns were Automata (portal to Mechanus), Fortitude (portal to Arcadia), Excelsior (portal to Mount Celestia), Tradegate (portal to Bytopia), Ecstasy (portal to Elysium), Faunel (portal to the Beastlands, Sylvania (portal to Arborea), Glorium (portal to Ysgard), Xaos (portal to Limbo), Bedlam (portal to Pandemonium), Plague-Mort (portal to the Abyss), Curst (portal to Carceri), Hopeless (portal to Hades), Torch (portal to Gehenna), Ribcage (portal to Baator), and Rigus (portal to Acheron). Passage through one of the gates always led to the first layer of the destination plane.

Portals also led from Sigil to the vicinity of each of the gate-towns, so it was possible to come through a gate from one plane and pass relatively quickly to Sigil or vice versa.

Inhabitants
Outsiders, natives of the Outer Planes, often spent time in the portal towns, since they had convenient access to their native homes. The towns were also home to many petitioners from the bordering planes. Because of the neutral ground of the Outlands, it was not uncommon to find a celestial arguing with a fiend in a bar in one of the towns.

History
Originally, the sixteen natural portals leading from the Outlands to the other planes were simple white disks on the ground and could lead to any of the Outer Planes. The destination was determined by the will of the majority of the persons attempting to use them. Over time, however, the regular flow of traffic through the portals led to the formation of communities built around the portals.

The gate-towns were only semipermanent. Sometimes they would vanish from the Outlands altogether, as if the entire settlement had been absorbed by the bordering plane. Some sages believed that the cause of this was the balance of moral and ethical outlooks of its residents. Too many lawful neutral citizens of Automata, for example, might cause the town to join with the orderly plane of Mechanus. Some citizens of the gate-towns strongly desired this to happen; other were more likely to act in a way opposed to the majority alignment as a means of keeping the town fixed in the Outlands.

During the reign of King Azoun Obarskyr IV, a half-elven paladin of Oghma from Cormyr was dispatched on a mission to explore the planes of existence beyond Toril. The paladin's name was Ambran the Seeker, and excerpts from his journal still survive to this day. In volume 7, Ambran described how he hired a bariaur guide to take him from Sigil to the Outlands. The lost volume 8 would have described his time spent in the town of Ribcage. Volume 9 tells of a journey from Ribcage to Automata. Once at Automata, he was able to witness the Modron Parade before continuing on to the River Ma'at. For reasons unknown, he abandoned his mission and remained on the Outlands. His final journal describes his journey from the Mausoleum of Chronepsis to the gate town of Bedlam, where he finally left the Outlands by traveling to Pandemonium.