As you ascend the main stairs, you find they continue up and up, all the way to the very top of the temple. It's as massive as a mountain, and similar to dwarvish make, but not as ornate on these levels as the main entry hall was.
Each landing leads to hall after hall, room after room. A sign at the beginning of each hall is inscribed with text almost too small to read, due to the amount of information stored on it. Each describes the various floors and rooms for that level, in addition to what floors exist above.
From what you can see, the rooms are shaped in such a way as to have held many uses. Perhaps once they were living quarters, too many to count. Faded scratches along the stone walls appear to have been made from furniture being moved. Some rooms still even have beds of wood and stone, that look liable to crack under too much weight.
Then they were possibly shrines, with old murals of other planes and peoples, great battles and historic moments, crystalline mountains and volcanic landscapes. Flaking and faded sections stand out to you with dabs of color, but much appears to have been rubbed clean from the stone.
They are now mostly storage, with crates and crates of grain, barrel after barrel of ale and stale water, bags--some broken-- spilling moldy dust that may have once been milled flour. Upper rooms held rare materials, animal carapaces, furs, clothing long worn and faded, and oils and incense for burial.
A few of the rooms you explore also have damage to the walls, where cracks in the wall let in whistling wind and light, and eddies of dust swirl in the corners. Its an eerie, lonely sound, and makes the building feel that much emptier.