Alan Lee’s paintings of Smaug, from an illustrated edition of The Hobbit.

There he lay, a vast red-golden dragon, fast asleep; a thrumming came from his jaws and nostrils, and wisps of smoke, but his fires were low in slumber.  Beneath him, under all his limbs and his huge coiled tail, and about him on all sides stretching away across unseen floors, lay countless piles of precious things…

—J. R. R. Tolkien, The Hobbit, chapter XII.

With a shriek that deafened men, felled trees and split stone, Smaug shot spouting into the air, turned over and crashed down from on high in ruin.

Full on the town he fell.  His last throes splintered it to sparks and gledes.  The lake roared in.  A vast steam leaped up, white in the sudden dark under the moon.  There was a hiss, a gushing whirl, and then silence.

— J. R. R. Tolkien, The Hobbit, chapter XIV.