Stephen Quayle and others have written extensively about this.Deuteronomy 3:11 For only Og king of Bashan remained of the remnant of giants; behold his bedstead was ... nine cubits was the length thereof, and four cubits the breadth of it.
A cubit equals approximately 1.5' and a span about 4", so King Og's bed was about 13.5' long and 6' wide, and Goliath was about 9'-4" tall.
There is a man now living in Russia who is well over 8' tall. He was recently interviewed on TV by an American reporter, although he generally avoids publicity and refuses to grant interviews. Unlike the very awkward appearance of most modern "giants" I have seen, he is fairly well proportioned and relatively normal in appearance except for his size.
People like him and mentions of giants in ancient literature make you wonder whether these modern day giants are somehow genetically linked to an extinct race of ancient giant humans, or are just examples of an occasional genetic accident. But it's hard to imagine that even a crew of 9' giants could have moved a 400 ton cut stone over 200 miles of roadless, mountainous terrain as the article states. I'm not saying that it didn't happen, but I think that such a feat would be virtually impossible or at least extremely difficult even today with our heavy earthmoving equipment.
Stephen Quayle and others have written extensively about this.