Sigil

Sigil, more commonly known as the City of Doors, is a city that rests atop the spire, like a spinning top. It's the nexus of mostly all portals, leading anywhere in the Multiverse one would want to go...if they knew how to get there. It's also where all 15 official factions make their base of operations. Sigil is ruled over by The Lady of Pain, an omnipotent and mysterious being that can run the city like clockwork. If you traverse the Planes, chances are you've visited or are planning to visit Sigil in search of something, since this endless city seems to have everything one would need.