It says in Genesis that there were "giants upon the earth in those days" right before it describes the building of the ark. It seems that they were of a savage nature, and that the cause of it was the children of light mingling with those of darkness. (?) (caused by the evils that had come upon the earth). You dont hear of good and gentle giants as far as I know. Goliath wasn't a good one. But, yes, I believe it. I have heard of evidence. Men of certain races may have been 10' tall or more. It seems that now, however, as we get closer to the end times, people will be smaller in stature and more sickly.