The Lord of the Rings: The Fellowship of the RingBook II, Chapter Five - The Bridge of Khazad-dûm
Gandalf had hardly spoken these words, when there came a great noise: a rolling Boom that seemed to come from depths far below, and to tremble in the stone at their feet.  They sprang towards the door in alarm.  Boom, doom it rolled again, as if huge hands were turning the very caverns of Moria into a vast drum.  Then there came an echoing blast: a great horn was blown in the hall, and answering horns and harsh cries were heard further off. There was a hurrying sound of many feet.
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The Lord of the Rings: The Fellowship of the RingBook II, Chapter Five - The Bridge of Khazad-dûm
Gandalf had hardly spoken these words, when there came a great noise: a rolling Boom that seemed to come from depths far below, and to tremble in the stone at their feet.  They sprang towards the door in alarm.  Boom, doom it rolled again, as if huge hands were turning the very caverns of Moria into a vast drum.  Then there came an echoing blast: a great horn was blown in the hall, and answering horns and harsh cries were heard further off. There was a hurrying sound of many feet.
Zoom Info

The Lord of the Rings: The Fellowship of the Ring
Book II, Chapter Five - The Bridge of Khazad-dûm

Gandalf had hardly spoken these words, when there came a great noise: a rolling Boom that seemed to come from depths far below, and to tremble in the stone at their feet.  They sprang towards the door in alarm.  Boom, doom it rolled again, as if huge hands were turning the very caverns of Moria into a vast drum.  Then there came an echoing blast: a great horn was blown in the hall, and answering horns and harsh cries were heard further off. There was a hurrying sound of many feet.