The Nephilim in the Old Testament were the offspring of the “sons of God” and the “daughters of men” before the Deluge, according to Genesis 6:1-4. Many early translations of the OT, as well as the King James version, preferred to translate the original Hebrew word as ‘giants’.

The World Heritage Encyclopedia offers a range of theories regarding the etymology of the word^(a).  Wikipedia has further background information on the subject^(c).

Jason Colavito has unearthed late 19th-century attempts to link the Cro-Magnons with the Nephilim^(e).

Ignatius Donnelly implied that the antediluvian giant Nephilim of the Bible were Atlantean, while others such as Blavatsky were more explicit.

>In Gateway to Atlantis, Andrew Collins proposed that Valum Votan was the original homeland of the Mesoamerican peoples. He further suggested that Votan, the culture bearer, belonged to the Hebrew giant race known as Nephilim^(g).<

In more recent times it was the work of the late Zechariah Sitchin that revived interest in the Nephilim, the Anunnaki and the existence of extraterrestrial visitors in ancient times. Unlike the more than dubious claims of Erich von Däniken, Sitchin’s ideas appeared to have a more reliable scientific foundation. However, this foundation was composed of Sitchin’s own interpretation of Sumerian texts, which has been heavily criticised^(b).

>In late 2017 and early 2018, a two-part article^(h)(i). by two young researchers, Jason Jarrell and Sarah Farmer added further criticism of Sitchin’s linguistic capabilities. In 2021, Jarrell & Farmer wrote a two-part article about the Anunnaki^(j)(k)., in which they concluded “that rather than making the Anunnaki the equivalent of the “Elohim” who created man in the Book of Genesis; they should more properly be compared to the Nephilim and the fallen angels described in Genesis Chapter 6, 1 Enoch, and other extra-biblical texts.”<

In 2019, Ryan Pitterson, tried to revive the idea of a connection between Atlantis and the biblical Nephilim but failed miserably. He is the author of Judgement of the Nephilim ^[1620],  which he claims to be “the first comprehensive biblical study of the Nephilim.” Jason Colavito disagreed^(f). Promotional interviews for the book gave him his fifteen minutes of fame, which is more than this book deserves.

Petros Koutouplis has also published a paper on Graham Hancock’s website, in which he investigates the biblical origins of the Nephilim and the possibility that they were ‘giants’, based on the evidence of the language of the Bible^(d).

^(a)  https://self.gutenberg.org/articles/eng/Nephilim  (link broken)  

^(b)  https://www.jasoncolavito.com/zecharia-sitchins-world.html

^(c) https://en.wikipedia.org/wiki/Nephilim

^(d) https://grahamhancock.com/nephilim-origins-koutoupis/

^(e) An Early Argument that Cro-Magnons Were the Nephilim – JASON COLAVITO 

^(f) https://www.jasoncolavito.com/blog/british-tabloid-uses-year-old-interview-with-nephilim-theorist-to-claim-atlantis-was-located-in-the-golan-heights 

^(g) https://www.andrewcollins.com/page/articles/cabrera.htm  *

^(h) http://www.ancient-origins.net/unexplained-phenomena/anunnaki-revealed-who-were-these-beings-ancient-astronaut-theory-what-do-021716  *

⁽ⁱ⁾ http://www.ancient-origins.net/human-origins-religions/zecharia-sitchin-and-mistranslation-sumerian-texts-009442  *

^(j) Anunnaki Revealed: Who Were These Beings of Ancient Astronaut Theory? – Part I | Ancient Origins (ancient-origins.net) *

^(k) Anunnaki Revealed: Finding the Nephilim in Myth, Giants Among Men– Part II | Ancient Origins (ancient-origins.net) *