Genesis Chapter 6 tells us about Giants before the Flood of Noah.
"There were giants in the earth in those days;
and also after that,
when the sons of God came in unto the daughters of men,
and they bare children to them,
the same became mighty men which were of old, men of renown."
Today's click through is to a recent but archived TV program which discusses this passage, its implications, and more.
I feel sure you will find it very thought provoking.
Pull up a chair. Get comfortable. And check this out.
HERE'S THE LINK to Steve Quayle: The Genesis Giants