The Egyptian Pyramids are generally accepted to have been constructed in the third millennium BC, in the period 2700 – 2150 BC. However, a number of investigators have inferred a much greater antiquity for some of these remarkable structures, particularly the Great Pyramid at Giza.
They believe that by pushing back the date for the construction of the Great Pyramid and/or Sphinx endorses the possibility that Plato’s early date of 9600 BC for the Atlantean War is factual.
Many and varied are the claims regarding their builders and their methods, including that they were built by refugees from Atlantis. For a long time it was thought that the pyramids had been built by slaves, possibly Israelites. Recent years has seen this idea debunked(at) and reinforced by papyri put on display for the first time in July 2016, which clearly indicate that the pyramid builders were paid and were not slaves (or extraterrestrials)(be).
A sober review of development of pyramid building and the technology involved was offered by Owen Jarus in June, 2016(bo).
The earliest historical references to the pyramids can be found in early Egyptian and Greek documents(ch).
The pseudoscience of pyramidology took off in the 19th century, with a range of outlandish claims(aq), based on external and/or internal dimensions of the Great Pyramid, supporting anything from the British Israelites or the early Jehovah’s Witnesses to being a source of divine prophecy!
Nevertheless, pyramidology was given a new twist in November 2015 when a Spanish architect, Miquel Pérez-Sánchez, added the old alphanumeric system of gematria to the mix and claimed that he had identified the name ‘Atlantis’ when ‘translating’ some of the dimensions in the structure of the Great Pyramid(by). Scott Onstott is also a modern advocate of the existence of Mathematical Encoding in the Great Pyramid(as)
For those interested in the possible significance of numbers and the Great Pyramid, there are three related papers available on Keith M. Hunter’s website(aw).
Many and varied are the claims regarding the pyramid builders and their methods, including that they were built by refugees from Atlantis(bl). October 2017 had Gerry Cannon & Malcolm Hutton claim(bx) that the Great Pyramid was built by an advanced civilisation, which may have been Atlantis! Graham Hancock holds similar views.
How the pyramids were built is still uncertain with a range ingenious theories on offer. At first it was thought that a huge ramp was used, until it was realised that such a ramp with the required gentle incline would require a greater volume of material than the Great Pyramid itself! Two suggestions that still have considerable support are that (1) many of the stone blocks were ‘cast’ in situ as proposed by Joseph Davidovits(bm) and (2) that an internal ramp within the pyramid was used as claimed by Jean-Pierre Houdin(bn).
Among the numerous mysteries related to the Great Pyramid is the fact that each side of the structure is actually slightly concave, making it the only known eight-sided pyramid, (pedants would probably claim nine sides, including the base). This feature was first photographed in 1940(al). The assumed accuracy of orientation and dimensions of the Great Pyramid was recently called into question by Mark Lehner and Glen Dash(bj).
Margaret Morris offers a comprehensive account of the features of the Great Pyramid and possible construction methods on her website(bb) and in three books . Morris is a supporter of Joseph Davidovits who proposed the controversial idea that the building blocks of the Pyramid were cast in situ. In 2007 petrographer, Dipayan Jana, refuted Davidovits theory and as far as I’m aware no rebuttal has been forthcoming from either Davidovits or Morris.
What may be relevant was what was found at Giza(bk) and described as ‘melted limestone’, which led Robert Schoch to consider it the result of ‘a plasma event’. However, it struck me that if Davidovits was correct, this ‘rock’ might instead be some of his liquid geopolymer that had been spilt and hardened in the sun!
Ralph Ellis, a British researcher, has studied erosion to be seen at the Giza, Meidum and Dashur pyramids and concluded  that there is evidence for an 8000 BC or earlier date for the construction of these structures(a). Ellis also has an article on the Internet outlining his evidence for an earlier date for the construction of the Great Pyramid.
More recently Robert Schoch announced the discovery of evidence of erosion INSIDE the Great Pyramid suggesting that a more ancient core had been exposed to the elements for a long period before being built upon to give us the structure we have today.
Edward Malkowski supports(ax) the ideas of Edward Kunkel(ay) and John Cadman(az), who believed that the Great Pyramid was designed to function as a water pump. However, Malkowski goes further, suggesting that this pump was used to generate subtle electrical fields that were used to assist plant growth, which seems unnecessary, considering the fertility of the Nile Valley renewed naturally by the annual flooding of the river.
Steven Myers has written two books(ba) on the subject of ancient Egyptian hydraulics.
*In 2009, Dean Talboys published a theory(co) which suggests that the remarkable internal features of the GP, including the King’s Chamber and the Grand Gallery were part of a device which used sea water to generate enough torque to drive an electric dynamo.Talboys suddenly ends his dissertation with the unexpected admission that “we are still left with the problem of what to do with the electricity it generates we could, at least, be a little closer to understanding why someone went to all that trouble”!*
Edgar Cayce ‘revealed’ in 1932 that the Great Pyramid was built over a hundred year period from 10,490 to 10,390 BC(ap).
Another writer, the late Joseph Jochmans related  how it was recorded that the outer casing stones showed water marks halfway up the height of the Pyramid before the Arabs removed them. Geologists have found evidence of a final catastrophic flooding event in Egypt circa 10000 BC. Furthermore radiocarbon dating of organic inclusions in a fourteen-foot layer of silt around the base of the Great Pyramid offered a date of around 9600 BC.
This suggested extended age for the pyramids has been incorporated in the argument to prove the existence of other advanced ancient civilisations that were concurrent with the 9600 BC date given by Solon for the antiquity of Atlantis.
Understandably, these revolutionary ideas have been met with fierce opposition by establishment archaeologists. This is a debate that will run for some time yet.
However, the oldest known papyri, discovered at the Egyptian site of Wadi el-Jarf offer evidence supporting a date of about 2500 BC for the construction of the Great Pyramid, which reinforces conventional dating theories. One of the documents, written by Merer an overseer, records details of the construction of the final stages of the G.P. (ce) This, of course, seriously undermines the extended antiquity for the pyramids by proponents such as Graham Hancock.
Apart from the disputed question of age of the Great Pyramid, its very structure has prompted its own share of debate with persistent claims that its location, dimensions and orientation have significance in the fields of astronomy, mathematics and geography. Lists of these connections are available online(p).
For Ignatius Donnelly the pyramids of Egypt and Central America were the result of a shared heritage originating in Atlantis. However, the millennia that separate the construction in the two regions would seem to militate against this idea. The Mayan pyramid at Mirador, in northern Guatemala, was thought to be the largest in the world, by volume, at 2.8 million cubic metres, however, the Great Pyramid of Cholula is 4.45 million cubic metres(au)(bq). This is now rivalled by the Mayan pyramid at Toniná, Chiapas(bd). The great Giza pyramid is 2.5 million cubic metres in volume.
Even more spectacular was the 1996 discovery of pyramids on the southern Atlantic coast of Brazil dated as early as 3000 BC, predating the earliest Egyptian pyramids by a few hundred years(I). However, two sites in Peru , Caral and Sechin Bajo, are claiming pyramid complexes with dates of circa 3500 BC(j). Very ancient pyramids have also been claimed for Crimea(af).
What is arguably the greatest concentration of pyramids in the world is to be found in the Lambayeque Valley of northern Peru, numbering 250, built of mud brick, and dated to circa 750-1100 AD. The late Philip Coppens referred to the valley in his book, The New Pyramid Age  and it was also the subject of a BBC documentary(an). His book reviewed pyramids as a worldwide phenomenon.
Apart from Mesoamerica, pyramids have also been discovered on the Canaries, Sicily, Sardinia and Mauritius(k), not to mention China. A website by Gabriele Lukacs dedicated to possible European pyramids is now available(g). The remains of three pyramids have also been identified on the Greek Peloponnese, one of which has been dated to 2720 BC ± 580 years. In 2005 the Bosnian-American ‘archaeologist’, Semir Osmanagic, announced that he had identified a gigantic manmade pyramid beside Visoko, 30 km north of Sarajevo. Highly publicised Excavations began in 2006. Readers should be aware that Osmanagic has expressed rather bizarre notions including a belief that the Maya were descendants of the Atlanteans who in turn arrived on Earth from the Pleiades! A French commentator, Douglas Moonstone, has a comparable belief, namely, that the Atlanteans came from the constellation of Orion and furthermore that the “Neanderthals fled their bases on another near planet, probably a planet of Sirius B and a planet of Alnitak, as we have seen in previous volumes, and they have saved Hopis, Sapiens, in a space station in orbit.”(cc)
On one side, we had Philip Coppens offering support for Osmanagic(cl), while on the other, an on-site investigation by Robert Schoch concluded that the Visoko ‘pyramid’ was probably not man-made!(cm)
Osmanagic updated his claims in December 2011(o). As recently as August 2016, he was still offering a spirited defence of his claims(bi). Gigantic pyramids have also been proposed for Germany by K. Walter Haug(ab) and demonstrated on his heavily illustrated website(aj).
Zecharia Sitchin, the controversial ‘alternative’ historian, entered the fray in 1980, with the claim that the only concrete evidence that the Great Pyramid had been built by Khufu, was an inscription forged by Colonel Richard Howard-Vyse(d) (see below). The Howard-Vyse forgery debate has been stirred up again by researcher, Scott Creighton, who produced copies of Howard-Vyse’s papers to support the claim of fraud(ah). If true, this would lend some support to a redating of the structure.
At the opposite end of the speculation spectrum, in a recent book by Emmet Sweeney  he claims that the pyramids were in fact far more recent, and bravely suggests a date of around 800 BC for their construction. In this regard it is to be noted that the Bible makes not the vaguest reference to one of the greatest wonders of the ancient world. It has been erroneously stated that Herodotus, a prolific recorder of trivia and who claims to have travelled as far south as Elephantine, failed to mention the pyramids. This is not true as can be seen in Book II of his Histories 124-134. However, it is possible that it was meant to say that Herodotus did not refer to the Sphinx! It has been claimed that he was describing the pyramids at Dashur and not Giza(ao)!
The most persistent question relating to the pyramids and in fact all megalithic structures is “how did they manage to build them using such large heavy rocks and blocks”? Many ingenious solutions are on offer but perhaps the most remarkable is that proposed by W. T. Wallington who has demonstrated(n) that using basic materials, which were available to the Egyptians, one individual can manipulate a 4500 kg stone block. His website includes a remarkable video clip of his method. A review of this video is worth a read.
More recently a collaboration between Matter Design and CEMEX Global R&D has demonstrated that irregularly shaped cement objects weighing many tons can be moved easily by hand, suggesting that the manpower required to build many ancient monuments was far less than is assumed today. The conclusion being that technique is the key to how many of the ‘impossible’ structures of the past were constructed(ci). Ashley Cowie has written an article in which he looks at how these techniques may have been applied to the construction of the megalithic walls of Cuzco in Peru, the ancient capital of the Inca(cj). Cowie also holds that a huge earthquake caused a major change in Inca construction methods(ck).
A recent (2014) study(ag) revealed that the Egyptians were able to move the pyramid building blocks over wet sand. “By using the right quantity of water they could halve the number of workers needed.” This is comparable with the documented method employed by the Chinese to transport 200/300-ton blocks used in the construction of their ‘Forbidden City’(ai).
In October 2018 it was revealed that the remains of a ramp flanked by two staircases with postholes was discovered at an ancient quarry at Hatnub in Egypt’s Eastern Desert. “Using a sled which carried a stone block and was attached with ropes to these wooden posts, ancient Egyptians were able to pull up the alabaster blocks out of the quarry on very steep slopes of 20 percent or more.”(cf) While this may explain how blocks could have been moved, with relative ease, to pyramid building sites, it does not tell us how the pyramids were actually constructed.
The idea that a ramp was used has been a popular idea for a long time, but weaknesses in the concept were soon apparent. For example, the material required to build some of the proposed ramps would have been greater than the pyramid itself. Franz Löhner has developed what he calls a ‘rope roll’ to demonstrate that simple technology available to the Egyptians could have been used to lift the pyramid’s blocks into place. Löhner has worked in a quarry and consequently has an intimate knowledge of the practicalities involved. He has co-authored a book (German only)  with Dr. Heribert Illig which expands on his idea and has developed an interesting website(cg), in English and German, with further information.
Some commentators, who cannot accept that the Egyptians built the pyramids, in desperation have interpreted the existence of the pyramids as ‘evidence’ of extraterrestrial visitations!(ae)
Ralph Ellis, mentioned above, is a controversial English revisionist of biblical and ancient Egyptian history, who daringly argues(b) that Mount Sinai, of Ten Commandments fame, was in fact the Great Pyramid of Giza! John Taylor (1781-1864) claimed in 1859 that Noah was the builder of the Great Pyramid . Even more imaginative was the claim by C.E. Getsinger in the 1920’s that Noah’s Ark was in fact the Great Pyramid(bp).
Finally, it appears that in order to satisfy the public interest in pyramids the meaning of the term itself has been extended to include a range of natural features as well as man-made structures. Robert Schoch is happy to see Newgrange as a type of pyramid, others see Silbury Hill as a pyramid(e), while some writers apply the term to mountains as is the case with Jeff Nisbet(f) who sees ‘pyramids’ in Scotland. Nisbet attempts to justify his view with a very tenuous link between ancient Egypt and Scotland incorporating freemasonry and Princess Scota(bh). Similar stories are widespread in Ireland where Scota is allegedly buried in Kerry in Gleann Scoithin, now known as Foley’s Glen. Scotia was another ancient name for Ireland. Andrew Power expands on the Scota story in his Ireland: Land of the Pharoahs  as well as Ralph Ellis .. This claim of an Egyptian link with Ireland has been repeated by Steve Preston in his Egyptians in Ireland . David Halpin, an Irish writer from Carlow, has also written a three-part paper on the connections between Egypt with Ireland(av). Francis J. and Francis P. Ward claim that druids from Ireland, which they consider to have been Atlantis, built the pyramids at Giza!(bt)
A recent (2010) site, lists(h) the eight largest pyramids in the world. A wide range of free papers, in pdf format, relating to the Giza pyramids is available online(l).
Perhaps even more dramatic is a recent claim(q) of a pyramid older and larger than the Great Pyramid at Giza, known as Mount Sadahurip in Garut, West Java, Indonesia .
July 2012 saw Linda Moulton Howe publish(r) a two-part illustrated article about an anomalous feature in Alaska which has been identified as a buried pyramid larger than the Great Pyramid at Giza. This feature was first identified twenty years ago, but the story appears to have been suppressed, according to a retired U.S. Counterintelligence officer who contacted Howe. A comparable claim has also been made for pyramids in Antarctica and later shown to be a hoax(w).
Now for light relief, earlier in 2012 a nonsensical report(s) of an underwater glass pyramid in the Bermuda Triangle emerged. I’m sure it will be soon followed by a sighting of Elvis creating crop circles in Antarctica.
August 2012 brought a report that two possible new Egyptian pyramid complexes have been discovered using Google Earth. However, subsequent inspection on the ground showed them to be less interesting(v). In May 2013, Peter James, a structural engineer, published a new theory on why the building of pyramids ceased(x).
In September 2013 it was reported(y) that researchers have discovered an underwater pyramid 60 meters high with a 8000 meters square base near the Bank De João de Castro, between the islands of Terceira and São Miguel” in the Azores. Shortly afterwards the Portuguese Navy denied the existence of any such structure(aa). This claim has now spawned its own website(ad).
Even more nonsensical was a report in the UK’s Daily Star which claimed that an underwater pyramid estimated to be between 3.5 and 11 miles across had been spotted on Google Earth, situated off the coast of Mexico in the Pacific(cd).
2014 began with a report that two idiotic Germans, Dominique Goerlitz and Stefan Erdmann, had chiselled off part of the ‘Vyse’ cartouche from inside the Great Pyramid, which led to an international incident. They claim that the objective of their foolhardy act was to demonstrate that the Pyramid is older than generally accepted and was in fact a remnant of the Atlantean empire(z).
2014 also saw the publication of Pyramid Gravity Force(ac) by John Shaughnessy in which he claims that “The pyramids were built to prevent and/or control tectonic plate movement, volcanic activity, tidal waves, major earth quakes, land movements and the magnetic field movements on Earth.” I suggest that all the Amazon reviews are read before purchasing.
It was recently revealed(ar) that, Ben Carson, a former Republican candidate for the US presidency, once proposed to an assembly of students at Andrews University that the Egyptian pyramids were built to store grain! This idea has been traced back to the sixth century,*when there was a belief that the pyramids had been the granaries of Joseph, as Julius Honorius (Cosmographia, c. 500 CE), Antoninus of Piacenza (Itinerary 43, c. 570 CE), and Geoffrey of Tours (History of the Franks 1.10, 594 CE), among others, all testify! This theory was later popularized by works such as ‘The Book of John Mandeville’, a hugely popular 14th century travelogue.”(bs)*
A June 2016 report revealed(bc) that the builders of the Great Pyramid had made a very minor miscalculation resulting in the west side being around 5 inches longer than the east side. The research team, led by Glen Dash and Mark Lehner, also noted that the pyramid is not oriented as precisely with the cardinal points as we have been led to believe since “The pyramid’s north-west being almost the same.” However, these very minor defects cannot detract in any way from the magnificence of the structure constructed so long ago.
In a 2018 paper(ca), Glen Dash returned to the very slight misalignment of the Great Pyramid with the cardinal points. “The builders of the Great Pyramid of Khufu aligned the great monument to the cardinal points with an accuracy of better than four minutes of arc, or one-fifteenth of one degree.” Dash claims that the engineers who designed the plans for the Great Pyramid have used the fall equinox to seamlessly align this pyramid to the cardinal points. “He also claims that all three major Giza pyramids exhibit the same type of error in that they are rotated slightly counter-clockwise from the cardinal points.”
Maxim Yakovenko was the founder of the world-pyramids.com website(bf) in 2008. It has a range of interesting articles that relate to pyramids around the globe. Unfortunately, the news section does not appear to have been updated over the past two years.
Another site offers a remarkable collection of old images of the pyramids dating back to the mid-nineteenth century(br).
November 2017 began with an exciting claim published in Nature magazine(bv) that a huge cavity had been identified above the Grand Gallery in the Great Pyramid of Giza. This discovery was made using non-invasive technology, which suggests that physical verification will require some degree of interference with the structure of the pyramid, which may not be allowed by the Egyptian authorities. This initial announcement was quickly followed by a refutation of the claim of a void over the Grand Gallery by Zahi Hawass(bw). Nevertheless, further investigation now (2019) seems to have confirmed the existence of this void(cn).
Not long after, it was reported in the UK’s Daily Mail that an Italian archaeoastronomer, Giulio Magli, believes that the void at the center of the Great Pyramid houses a throne made from meteorites, used to help the pharoah in the afterlife(bz). Magli has previously received public notice with a paper which explored the possibility that Göbekli Tepe had been constructed to “celebrate and successively follow the appearance of a new, extremely brilliant star in the southern skies: Sirius.”(ca)
(a) See: Archive 2925
(b) See: Archive 2926
(d) See: Archive 2494
(j) See: Archive 2138
(n) http://www.theforgottentechnology.com/newpage1 (offline May 2017)
(p) See: Archive 3620
(r) http://www.earthfiles.com/news.php?ID=2000&category=Environment (subscribers only)
(af) See: Archive 3619
(ah) See: Archive 2806
(am) http://www.bibliotecapleyades.net/piramides/coppens_pyramids08.htm (offline see Archive 2564)
(ao) See Archive 2818
(bb) See: Archive 3057
(bn) See: Archive 3631
(bp) The Thomson Review, Thomson, Illinois, July 19th, 1922 – p.3
(bx) See: Archive 3618
The Megalith Builders, who date mainly from the Neolithic Period, are frequently identified with Plato’s Atlanteans. Their remarkable structures were built between the middles of the fifth and second millennia B.C., a period that is compatible with final days of Atlantis according to Plato. The building of megalithic structures in Western Europe appears to have ended just before the beginning of the Bronze Age – coincidence?
Proponents of the idea of a megalithic building Atlantis see the location and extent of the megalithic structures as being in agreement with Plato’s description, particularly his reference to Atlantean influence extending as far as Tyrrhenia and Egypt.
However, there are many features in Plato’s narrative that do not conform to our current knowledge of the megalith builders. There is no evidence that they had writing, irrigation technology or the navigational skills to mount an attack on Egypt/Athens or any other characteristics ascribed to the Atlanteans by him.
On the other hand, if these attributes are just literary flesh applied to a skeleton of historical truth the possibility of a link between the Atlanteans and the megalith builders still remains.
Atlantis enthusiasts are quite happy to associate the megalith builders with Atlantis, as it provides something tangible to enhance the credibility of Plato’s narrative pointing to sites such as Stonehenge or the Maltese Temples. British researcher Robert John Langdon has gone further and proposed that the megalith builders originally came from Africa and settled in Doggerland at the end of the Ice Age, where they established Atlantis. When Doggerland was submerged they migrated to what is now mainland Britain, where they built Stonehenge as a memorial to Atlantis.
While not a new idea, a megalithic connection with Atlantis has recently been given further attention by the French writer Sylvain Tristan who was inspired by Jean Deruelle and Alan Butler. Alfred deGrazia also joined this club as well as the German author Helmut Tributsch who has added his support to the idea of a megalithic Atlantis, specifically locating its capital on the island of Gavrinis in Brittany. A similar claim has been made by Hank Harrison who also believes that the Morbihan region was an important Atlantean centre if not the location of its capital. Further support for a megalithic Atlantis has been given by Walter Schilling who places Plato’s city in the Bay of Cadiz. Robert Temple has recently offered grudging support for the concept of Atlantean megalith builders.
Iberia is also home to very many megalithic strucures of varying types. Recently, lower waters in a Spanish reservoir revealed once more the impressive 144-stone Dolmen-de-Guadalperal, situated roughly halfway between Madrid and the Portuguese border(z) . Efforts are being made to ensure its preservation before the water levels rise again.
As far as I am aware classical writers make no obvious reference to the megalith builders, nor has this omission been commented on by modern writers. However, the numerous indirect references to Atlantis by the same ancient writers are deemed inadequate, which seems consistent with a dearth of information regarding early history.
It appears to me that other questions that have not been definitively answered relate to the identity of the megalith builders, why they stopped building and what happened to them. Another thought is that if the megalith builders lived at the same time as the Atlanteans, is it not strange that both disappeared around the same time, or did they?
Parallel with the megaliths of the eastern Atlantic seaboard are the megaliths of North America. Who built them and when? Are they evidence of very early pre-Columbian voyagers from Europe?(b)
An interesting article combining all the strange aspects of megalith building can be read online(c) which certainly offers food for thought. A paper(d) published in September 2013 gives a good overview of megalithic studies during the past few decades. Walter Haug’s well illustrated website(k) offers a range of previously ignored megalithic sites in Germany.
Much nonsense has been written about the megalith builders, particularly on the Internet, where you find daft ideas such as attributing their construction to aliens(a). The suggestion that extraterrestrials had the technology to travel in space but when they land on earth they have to build observatories with stone is just silly.
A valuable website dealing with the global spread of megalithic monuments, is The Megalithic Portal established by Andy Burnham(g), which has regular updates. Other useful sites are Stone Pages(h) and Megalithic Ireland(i). Another site worth a look is from Sjur C. Papazian(l). There is also a site(j) dealing specifically with the dolmens of Corsica and Sardinia.
In the Middle East dolmens stretch in a line from the Caucasus(s)(p) to the Yemen with a remarkable concentration of them in modern Jordan(m), a fact which prompted a former Dutch ambassador to Jordan, Gajus Scheltema, to write Megalithic Jordan. Jordan is also home to an ancient mysterious 150 km wall, which was 1-1.5 metres high.(u)
Dolmens are also found in more distant lands such as India(r), Korea(n)(v) and Japan(o). It is difficult to look at the worldwide distribution of dolmens and not consider the possibility of some form of global cultural diffusion! Rarely discussed are the widely dispersed megalithic remains found throughout the Pacific islands(q).
There is a well-illustrated website offering an overview of the megalithic culture of Western Europe and the Mediterranean(t).
In February 2019 the Smithsonian Magazine had a report telling us that “Bettina Schulz Paulsson, an archaeologist at the University of Gothenburg, reexamined some 2,410 radiocarbon dating results that have been assigned to Europe’s megaliths and put them through a Bayesian statistical analysis. Based on the picture the data present, Schulz Paulsson believes that the megaliths were first constructed by dwellers of northwest France during the second half of the fifth millennium BC.” (w)
Some years ago, the renowned English archaeologist, Aubrey Burl, concluded after twenty years of study that French immigrants had built Stonehenge(aa). More recently, Mike Parker Pearson, a leading Stonehenge expert, has also endorsed this idea of a French origin for megalith building(x).
The interesting claims of Schulz Paulsson, who place the origins of megalithic construction to Brittany in the fifth millennium BC, may be challenged by a little-known counterclaim that tombs in the Ox Mountains in the west of Ireland have been dated to the seventh millennium BC(y). However, my personal view is that it would be more likely that the practice of megalith building would have spread from the east rather than from Ireland westward!
A rational explanation for the construction of cyclopean masonry has been offered by Professor of Architecture Jean-Pierre Protzen and demonstrated on a YouTube clip(f).
(q) http://davidpratt.info/easter1.htm (section 10)