I've talked about giants several times before on this forum and I also think it's an interesting topic. Check out this page for reports of skeletons that have been found:
http://davidpratt.info/ape2.htm#a2 (scroll down to section "Giant humans")
There have also been found giant skulls which have double rows of teeth [1], and giants with six fingers. The Bible mentions "a huge man" who had six fingers and toes in 2 Samuel 21:20. The giant races have various names in the Bible, like nephilim, rephaim, anak and anakim. Giants are also mentioned in many other religions and mythologies.
"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." (Genesis 6:4)
Because of this interbreeding, there have been born giants thousands of years after that, because it takes time for the giant genes to get evenly distributed, so that people are born with the same height. Even today the size difference among humans is still more diverse than between animals.
The giant genes weren't the only ones that were passed on, because they were "sons of God", which means that they were descendants of God (like Jesus), and had supernatural powers, which were also passed on. What the sons of God did to humanity is that they sacrificed their divinity, so that we could evolve faster, because we would get their genetics. Because of this sacrifice, they had to be reborn to earth into human bodies again, instead of "going to heaven".
Because of this ancient sacrifice (which according to theosophy happened hundreds of thousands of years ago), there are still very rarely born people who have all of the "divine DNA", and these are people like Jesus and Krishna for example. Many geniuses that have lived have also inherited parts of that DNA.
Another interesting and related topic is the elongated skulls that have been found all around the world:
"The cranial volume is up to 25 percent larger and 60 percent heavier than conventional human skulls, meaning they could not have been intentionally deformed through head binding/flattening." [2]
(when people were no longer born with large elongated heads, the primitive people tried to imitate the "gods" by brutally and artificially elongating their heads, so that they also would also be respected as kings)
Among royalties, large hats have always been common, like in ancient Egypt for example. I believe that is because (like history/mythology tells us), kings in ancient times used to be "gods" or their descendants, and they had larger brains (and bodies too, sometimes), wisdom and powers than ordinary humans living at the same time, which is also why they got into positions of power ("the divine right to rule").
That's where the idea of "royal blood" also comes from, because the genetics and supernatural powers of the "divine" race of people were passed on. Today, the royalties are just normal people though, because parts of the DNA of the ancient races have been gradually evenly distributed into all people.
Without the sacrifice of the sons of God in Atlantis [3], we would have none of the technology we have today, because our mind would still not have been awakened to that degree.
[1]
http://www.sott.net/article/256712-A-giant-mystery-18-strange-giant-skeletons-found-in-Wisconsin-Sons-of-god-Men-of-renown
[2]
http://www.infowars.com/dna-results-for-the-nephilim-skulls-in-peru-are-in-and-the-results-are-absolutely-shocking/
[3]
http://www.theosociety.org/pasadena/sd/sd2-1-12.htm
See also:
https://en.wikipedia.org/wiki/Giant_of_Castelnau
http://www.sacred-texts.com/atl/soa/soamap.htm