At the center of the Outlands, like the axle of a great wheel, is the Spire, a needle-shaped mountain that rises high into the sky. Above this mountain’s narrow peak, not part of the Outlands but a plane in its own right, floats the ring-shaped city of Sigil, its myriad structures built on the ring’s inner surface. Creatures standing on one of Sigil’s streets can see the city curve up over their heads and—most disconcerting of all—the far side of the city directly overhead. Called the City of Doors, this bustling planar metropolis holds countless portals to other planes and worlds.
Sigil is a trader’s paradise. Goods and information come here from across the planes. The city sustains a brisk trade in information about the planes, particularly the commands or items required for the operation of particular portals.
The city is the domain of the inscrutable Lady of Pain, a being whose purpose and goals are unknown to even the sages of her city. She appears almost human, although she most definitely isn’t. She wears ornate robes that shroud her body, and a mantle of blades coated in blue-green verdigris surrounds her masklike face. No one is certain who or what exactly the Lady of Pain is, but it’s widely accepted she’s a being on par with deities. Is Sigil her prison? Is she the fallen creator of the multiverse? No one knows—or if they do, they aren’t telling.
Planescape: Adventures in the Multiverse includes extensive information on Sigil.
In the cosmopolitan streets of Sigil, creatures from across the multiverse coexist in uneasy peace.