The Great Shaft was a tunnel dug by the D'ni as a means of reaching the surface of the Age of D'ni. The digging was done primarily by the Guild of Miners and the Guild of Surveyors and headed by Master Telanis. However, after two deaths and the near death of Veovis, The Council shut down the project, even though it was near completion. The Great Shaft leads directly up into the volcano at The Cleft and was used by Ti'ana to reach the city of D'ni.
The Great Shaft was a joint project of the Guilds of Surveyors, Miners, Stonemasons, and Cartographers. These tunnels are coated in nara, a form of highly processed material which is nearly indestructible, and gives off light. The other caverns are now mostly dark.