Lying within the Yden, the Labyrinth covers the ridge that connects the Plain of Thrones to the Pillar of Heaven. It consists of an immense hypostyle hall in which each column is in fact a mausoleum for past God Emperors, Empresses and other important personages from the House of the Masks. There are over one thousand of these column mausolea. Originally they were free standing. It was only later that they were spanned by arches and that the whole structure was roofed. The Lower Palace is partially built into the south-western wall of the Plain of Thrones but it also spills into the Labyrinth.

The two depressions that 'nip' the cross-section of the Pillar of Heaven contain the only ways by which it can be climbed. The north-western depression contains the Rainbow Stair. The south-eastern contains the Ladder which Carnelian and Osidian use to descend to the Yden.

The diagrams show the contour lines. The northwestern portion of the Yden melts into lagoons.