"Wait, that giant donut up there was where we just came from??"
--Clueless Prime, after taking a portal from Sigil to the Outlands
Sigil is the heart of the Planescape setting. That's why I decided (as editor) that fleshing out the City of Doors should be the target of UPS' first major project. Feel free to work on other aspects of UPS if you have an idea you're dying to share-afterall, as the setting's centerpiece, there's little out there that doesn't tie into Sigil somehow.
Let me lay out how I envision Sigil in UPS-as modernization swept the Multiverse, tall skyscrapers seemed to grow faster than Razorvine in the City of Doors. Only the Lady's Ward, with its grand monuments from the Age of Pain and influential elites that protected the "old neighborhoods", was spared the break-neck pace of construction. By the the time all was said and done, the five other wards essentially consisted of 3 levels. In typical planar fashion, Cagers adopted the terminology of the planes to describe the new shape of their city. The Upper Level is where bloods go to be seen and recognized. Mid-Level is where folks go to take care of their private needs. Finally, the Lower Level is the part of Sigil that's left out of sight and out of mind as much as it can be helped.
The parallel between Sigil's 3 levels and the distinction on the Great Wheel between Upper, Neutral, and Lower Planes is obvious. With any such parallels, though, the Cage adds a twist. The Upper Level has plenty of seedy activity-from corporate boardrooms in the Guildhall Ward to abandoned stadiums in the Hive. On the other hand, Sigil's essential supplies, such as water and electricity, originates somewhere in the Lower Level (most likely multiple locations).
As implied earlier, a given level in one Ward is much different than the same level in a different ward.
The next section will be on Sigil's centers of Power (political, factional, economic, religious, societal, illicit, etc). Post your thoughts on this, as well as my vision of modern Sigil.
Hm... *grin* Jester's Palace here I come... mauahaha.
It should be of interest to note that the faces of most of the Golden Lords have probably changed significantly save for those who are already immortal. We haven't picked *how* far in the future we are yet, but there's going to be a lot of cutters needing to be defined for this.