The city Oroboro is a great ring larger than any other city, larger than many worlds.
Everything strange and everything precious is fated to pass through it--and also a great many things that are neither. It is (Ill-)Fortune’s Wheel, the Nexus of All Tales.
The city encircles the double-ended Tower, where the Sandmen priests say the Goddess sleeps and dreams the multiverse. Just beyond the oneiric event horizon, Oroboro is stable (mostly) and rational (sometimes) and permanent--so long as the Goddess sleeps.
Some cynics say there is no Goddess and the Tower is empty. To preserve their power, the Sandmen hide the truth: the Architect of All has abandoned creation and is likely to be found in a brothel or ginhouse in Oroboro.