'Following his lead, the Company passed under the northern arch. They found themselves in a wide corrider. As they went along it the glimmer grew stronger, and they saw that it came through a doorway on their right. It was high and flat-topped, and the stone door was still upon its hinges, standing half open. Beyond it was a large square chamber. It was dimly lit, but to their eyes, after so long in the dark, it seemed dazzingly bright, and they blinked as they entered.
Their feet disturbed a deep dust upon the floor, and stumbled among things lying in the doorway whose shapes they could not at first make out. The chamber was lit by a wide shaft high in the further eastern wall; it slanted upwards and, far above, a small square patch of blue sky could be seen. The light of the shaft fell directly on a table in the middle of the room: a single oblong block, about two feet high, upon which was laid a great slab of white stone.
'It looks like a tomb,' muttered Frodo, and bent forwards with a curious sense of forboding, to look more closely at it. Gandalf came quickly to his side.' JRR Tolkien: The Lord of the Rings: The Fellowship of the Ring: Book II, Chapter 4: A Journey in the Dark