Question: “I wonder, how are we to think of the Giants from the Old Testament? Can it be that there was another race of beings that were drowned in the great flood? Why would God do this? Were they made in his image as well? What was their purpose? Is the evidence of them in the archeological record presented in recent years true?”
The first mention of giants found in Scripture is in Genesis 6:1-4:
“And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them, That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose. And the Lord said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years. 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.”
There are a few early Christian writers that took this to refer to demons mating with humans, and producing giants, but most of the Fathers rejected this interpretation, and said that the "Sons of God" are those of the godly line of Seth, who mated with women of the ungodly line of Cain.
Fr. Seraphim (Rose) notes:
"Some have speculated that the 'sons of God' were heavenly beings or angels. The Holy Fathers were aware of this interpretation and they refuted it, saying that angels cannot beget men." [Here a footnote adds the following: "The identification of the 'sons of God' as angels or heavenly beings was based in part on the apocryphal book of Enoch....Some of the early Christian writers mistakenly accepted this interpretation....The first extant Christian reference to the 'sons of God' as descendants of Seth is in the Five Books of Chronology by the early Christian writer Julius Africanus (A.D. 200-245) (Ante-Nicene Fathers, vol. 6, p. 131). This interpretation became the consistent teaching of the Church, being set forth on theological grounds by St. John Chrysostom (Commentary on Genesis 22:6-7), St. Ephraim the Syrian (Commentary on Genesis 6:3, Hymns on the Nativity 1:48, Hymns on Faith 46:9, Hymns against Heresies 19:1-8, and Hymns on Paradise 1:11), St. John Cassian (Conferences 8:20-21), Blessed Augustine (City of God 15:23), St. Gregory Palamas ('Topics of Natural and Theological Science' 62), St. Athanasius (Four Discourses against the Arians 4:22), St. Cyril of Alexandria, and others."] (GENESIS, CREATION and EARLY MAN, page 244, quoted by "Angels Marry Women? Nephilim, sons of God, and Genesis 6:1-5" By Robert E. Gentet).
And so the giants of Scripture were not a different species, but simply men who were extraordinarily large. The best known giant in the Bible is Goliath. If the Hebrew Masoretic text is taken at face value, Goliath would have been 9 feet 9 inches tall (six cubits and a span). However, according to the Septuagint and Dead Sea Scrolls texts, he was 6 feet 9 inches tall (four cubits and a span) [see J. Daniel Hays, "Reconsidering the Height of Goliath", JETS 48/4].
The tallest man in modern history was Robert Pershing Wadlow, who was just over 8 feet 11 inches:
Robert Wadlow compared to his father, Harold Franklin Wadlow
Assuming the Septuagint text is correct, Goliath would have to look up to Robert Wadlow, who was more than 2 feet taller than he was.