The Megalithic Yard is a controversial unit of measurement originally proposed by Alex Thom following a study of hundreds of megalithic sites in Britain and Brittany. Very many attempts have been made to verify his conclusions, but to no avail. Wikipedia(d) offers an interesting overview of the wide-ranging theories that the controversy has thrown up.
Humans have used their body parts as measuring tools right up to the present day, e.g. foot, finger or hand, so it was not surprising that the human pace provided a unit of measurement which has been suggested by many as the original megalithic ‘yard’.
Not unexpectedly, some researchers, such as Ulf Erlingsson(a), Sylvain Tristan(b) and Jim Allen(c) have endeavoured to link the megalithic yard with their interpretation of Plato’s Atlantis, sometimes with convoluted associations with ancient Egyptian and/or Sumerian metrics!
There is also an ancient unit of measurement known as the ‘long foot’ of 12.7 inches (32.2 cm). In early 2019, archaeologists from the University of Manchester and University College London concluded, after a study of three small carved chalk ‘drums’, that they “could be ancient replicas of measuring devices used for laying out prehistoric monuments like Stonehenge.” They found that “a string wound 10 times around the smallest of the drums would give a measure of exactly 10 long feet — a length used to lay out several ancient henge monuments“(e).
David Hildebrandt is an American researcher, who has published two books, The first, Forbidden Fruit, is a 784-page tome  with the self-explanatory subtitle of The Evolution of Human Intelligence. He has also turned his attention to the subject of Plato’s Island in Atlantis – The Reawakening ,in which he offers a vigorous attempt to convince readers that Britain had been home to Atlantis, with Stonehenge as the Temple of Poseidon.
Many aspects of his hypothesis have already been expressed over past centuries, but his synthesis does offer some new perspectives. For me, his dating, location and identity of the Atlanteans does not ring true, particularly why Stone Age people in Southern Britain would want to launch an attack on Athens, over 2,000 miles away, a city-state which did not even exist at the time. Those early Britons did not have the wheel, yet Plato tells us that the Atlanteans had chariots!
Thomas J. Krupa (1930- ) is the author of Biblical Flood, Noah’s Ark and the Star of David  , in which he makes a number of startling claims. The book begins with an attack on the theory of plate tectonics. He then moves on to the opening of Drake Passage(a), conventionally considered to have taken place around 40 million years, but dated by Krupa to just 29,000 years ago, eventually leading to the ending of the Ice Age.
He also proposes the existence of an isthmus or landbridge between Sicily and North Africa and that the limestone structure was weakened by the rising Atlantic and rain erosion and finally fractured by an earthquake, which led to the flooding of the Black Sea and further afield. He then contends that a backwash from this flooding created the Strait of Messina.
He believes that this Sicilian isthmus “is a stronger contender for the location of Atlantis than every other place that I am aware of.”
Krupa then moves on to discuss Noah’s Ark, which he claims had a keel shaped like the Star of David and furthermore that the ‘Star’ was incorporated in the design of Stonehenge! Coincidentally, Robert John Langdon has also linked the hexagram or Star of David with the layout of Stonehenge(b).
Advancing to even more contentious matters he maintains that the Kaaba in Mecca is intended as a replica of the Ark and to crown it all that Alexander the Great is buried within the Kaaba!!!
Emad Kayyam is a medical doctor from Jordan and who is also described as a multidisciplinary researcher. He has touched on the subject of Atlantis, locating it in the Atlantic(a). However, after that, I was lost when I found that he was comparing his proposed layout of Atlantis to human nasal cavities! He also compares the human eye with Stonehenge(b) and the tear duct with the Red Sea (d)! Another gem is his observation that the tilt of the eyeball in its socket is comparable with the tilt of the Earth’s axis(e)!
I cannot understand what he is suggesting or trying to prove, perhaps some of his TV interviews might throw some light on his ideas, but unfortunately the clips are in Arabic(c).
(b) https://www.streamica.com/#v/f4dEEwQySBA (Offline March 2015) see (e)
(c) https://www.streamica.com/#v/wJTu0Tjw8Nk (Offline March 2015) see (e)
Louis Millette, is a Canadian commentator who claims to have identified the location of Atlantis in the region of the Guadalquivir River in Spain’s Andalusia, maintaining that Tartessos, Tarshish and Atlantis were all the same. He has posted a set of three satellite image(d) to support his contention, unfortunately, I cannot see anything that might be related to Atlantis. His brief video clip(e) is equally uninformative.
However, Millette is a firm believer in extraterrestrial visitors(a), which for me is sufficient reason to consider him an unreliable researcher. He also claims to have located the ‘Hanging Gardens of Babylon’ in Nineveh,>(now on the outskirts of Iraq’s city of Mosul),<an idea already proposed by Stephanie Dailey of Oxford University as early as 1992(c)>and later (2020) adopted by Anthony Woods.<Even more provocative is the suggestion from Constantinos Ragazas that the correct title should be The Hanging Gardens of Göbekli Tepe!(f)
Millette promises startling revelations regarding Stonehenge in June 2015. However, a brief posting(g) on the academia.edu website, consisting of some text and three images reveals nothing!
(d) https://yourshot.nationalgeographic.com/profile/332999/ (link broken)
Robert John Langdon is the Brighton based British author of Prehistoric Britain: The Stonehenge Enigma, the first part of a trilogy(b). The book was first published in 2010 with a second edition brought out in 2013. The final chapter of the second edition is now available online(a). In it, he contends that the megalith builders came from Africa to Doggerland at the end of the last Ice Age, however, as the waters rose submerging Doggerland, the megalith builders had to move to higher ground on what we now know as Great Britain, eventually constructing Stonehenge as a memorial!
Langdon claims that the Altar Stone at Stonehenge points to Doggerland, which he identifies as the location of Atlantis. He also claims that the Slaughter Stone is in fact a representation of the flooded world of those megalith builders.*Langdon is highly critical of the generally accepted interpretation of various features found at Stonehenge, listing 13 items that he claims “don’t make sense”(f).*
Another of Langdon’s claims is that “Cro-Magnon/Atlanteans colonised America” based on a study of blood group distribution(e).
In September 2014, Langdon changed his website(c) and published further excerpts(d) from his books.
His second volume was published in 2016.*There are also a number of related free pdfs books available on his website.*
The Bell Beaker People identified by their distinctive pottery existed from around 2800 BC until 1800 BC. They occupied large areas of Iberia, Central Europe and the British Isles as well as some of the western Mediterranean islands. Melville Nicholls claims that they originated in Portugal. Associated with them are the Wessex people divided into Wessex I and Wessex II, who are found in western Europe and southern Britain, the latter, dated to 1650-1400, were involved with the construction of the later stages of Stonehenge.
Uwe Topper associates the beginning of metallurgy with the Bell-Beaker People(e).
Nicholls and others(b) have linked Atlantis with the Bell Beaker culture, identifying a location near Gibraltar as the site of Atlantis. He published his views in Children of the Sea God, a 2013 Kindle ebook(a) and a second ebook, The Real and Imaginary Atlantis generally reprising the first, later the same year! Further comment from Nicholls can be found on an internet forum(f).
David D. Miner, is an American Doctor of Medicine, who published a paper linking the Beaker People, Atlantis and Salisbury Plain. He makes a serious and imaginative effort to explain details in Plato’s narrative in the context of this proposed association.
The Beaker People are also claimed to have crossed the Atlantic, where they have been linked to the Adena culture of North America. A leading exponent of this theory is undoubtedly Jay S. Wakefield, co-author of How the SunGod reached America . He has reprised his views in a 2018 paper on the Diffusion & Migration website(c)(g) . Others have expanded on his concepts(d).
(b) https://widespreadblyss.blogspot.ie/2013/02/platos-atlantis-and-bell-beaker-culture.html (link broken Sept. 2018)
Melville Nicholls is a senior research scientist at the University of Colorado where he studies atmospheric science, mainly relating to hurricanes. In May 2013, he published Children of the Sea God as a Kindle ebook. One of his main contentions is that Atlantis existed during the early Bronze Age at the time of the Bell Beaker culture, >which he claims originated in Portugal around 2800 BC.<
He also contends that Britain was the large island of Atlantis described by Plato. However he also proposes that the main port city of Atlantis, with the concentric rings of land and water was situated in southwest Spain near Gibraltar. He proposes that this port was destroyed by an event such as a tsunami.
While all these features have been proposed individually as characteristics of Atlantis, Nicholls brings them together in a comprehensive theory, but not without indulging in a liberal amount of speculation.
He devotes a considerable amount of space attempting to link Stonehenge with the Atlanteans. While I was not won over by Nicholl’s book, it is worth a read and might best be studied along with Donald Ingram’s book, The Unlost Island.
In November 2013, Nicholls published a second ebook, The Real and Imaginary Atlantis, in which he revisits his theory of a British/Spanish Atlantis and its relationship to the Bell Beaker People. In conclusion, he seems to reluctantly write that “I still come down in favor of the theory that Plato invented the story as the one most likely to be correct.”
Arkaim is a 2nd millennium BC archaeological site in Russia, although some date it to 7000 BC(c). The site was rediscovered in 1987 just as the locality was at risk of submersion due to a proposed nearby dam-building project. This was later put on hold.
It has been compared with Stonehenge(b), troy towns(d) and Plato’s Atlantis(a). It is also claimed as a psychic ‘hotspot’’(e) as well as a site of UFO activity!
The Atlantis link is just fanciful and does not stand up to the most cursory examination. For example, there is no evidence that Arkaim was ever submerged as Atlantis was recorded to have been by Plato.
A 2014 article that compared Arkaim with Stonehenge commented that “It would seem that Arkaim is an even better astronomical observatory than its namesake.”(g)
Victoria Lepage, a purveyor of mystical twaddle has endeavoured to incorporate Arkaim into her pathetic view of world history(h).
Dale Drinnon’s website included an extensive entry on Arkaim in Feb. 2012(f).
August 2015 produced a report(i) that a 2,000-year-old skeleton of a female, with an elongated skull had been unearthed in the vicinity of Arkaim. Apparently, this was the result of a local tradition of head-binding.
Manuel Vega (1967- ) was born in Spain and studied Chemistry there and later worked as a research scientist in America and Japan. He travelled widely in the Far East before returning to the United States where he spent five years training a Buddhist monk before resuming a more secular life.
In 2012 he published Sailors of Stonehenge in which he reviews the principal megalithic sites of Western Europe, including some interesting speculation. For example he describes the English Avebury complex as a site of ‘monarchical renewal’ and proposes related ceremonies at Stonehenge. Another of what I consider his more fanciful ideas is his suggestion that Ireland’s Boyne Valley, which includes Newgrange, was used as a ‘royal funerary complex’ for dead English kings! He maintains that the location of many of these sites was determined by the position of astronomical features in the night sky.
Vega ends the book with a chapter on Atlantis, which he locates in the Atlantic and identifies the Atlanteans as the Megalith Builders. “By the end of the 4th millennium BC they designed a huge celestial mirror over the Atlantic territories, which served to regulate themselves politically and religiously (implementing Heavens on Earth). The largest and most unique constructions, such as those at Carnac, Avebury, Stonehenge and Newgrange, were royal monuments erected at key sites of this celestial mirror according to a megalithic technology designed to attain the rebirth of the sacrificed kings again as princes, keeping an unbroken royal lineage.”
* Vega returned to the subject of the megalith builders in 2015 with the publication of Voyage Zero. However, in 2017 he became even more contentious in Madrid is Atlantis, which as the title implies, claims that Atlantis was located in the vicinity of the author’s native city.*
I found it very hard to accept most of his claims.
Those interested in reading more of Vega’s ideas can read his blogs(a).