Immeasurably into the past, in primordeal times when the world was yet but roughly hewn by the blows of time and mind, was the Time of Giants.
The giants of old must have been less savage than the ones whom are extant now, for they built mighty works out of stone, which may be seen to this day.
Humanity has no record of this time, save in the form of tales of human heroes outwitting half-witted, man-eating giants, and these may very well record events of the 6th Age.
Mostly, the works of the giants are found in utter ruin, foundations of mighty houses, worn down to the base like the teeth of an old crone. Sometimes one discovers well-preserved blocks lying singly in the middle of nowhere.