Tu'narath is the central city of the Githyanki in Dungeons & Dragons. Ruled over by the lich-queen Vlaakith CLVII, it resides in the Astral Plane (or Astral Sea) and is built atop the enormous, world-sized petrified corpse of a long-dead deity referred to only as "The One in the Void". Identification is rather tricky as its face has been chiseled off, though whether this was done by the githyanki or not is unknown.
The 5e book Mordenkainen's Tome of Foes has many details on the place, including some rad art. Apparently Thayan wizards have been trading for the god's petrified organs or some shit.
|The Gith of Dungeons & Dragons|
|Races:||Duthka'gith - Gith - Githyanki - Githzerai|
|Undead:||Kr'y'izoth - Tl'a'ikith|
|Individuals:||Vlaakith CLVII - Zaerith Menyar-Ag-Gith - Zerthimon|
|Places:||Shra'kt'lor - Tu'narath|
|Miscellaneous:||Crown of Corruption - Gish - Scepter of Ephelomon|
|Adventures:||Incursion - Scales of War|
|The Cosmology of Planescape|
|Inner Planes||Ethereal Plane||Prime Material||Astral Plane||Outer Planes||Ordial Plane?|
| Demiplane of Dread
Plane of Shadow
| Plane of Mirrors
World Serpent Inn