Nabta Playa is a megalithic site situated 100 km west of Abu Simbel. It is the only known megalithic circle in Egypt, although in this instance ‘megalithic’ may be a misnomer as the components could have been erected by one person. A number of astronomical alignments have been identified at the site(a) .
Although first rediscovered in 1974, it became known to a wider audience when astrophysicist Thomas G. Brophy published his book, The Origin Map in 2002. The importance of Nabta Playa was further highlighted in a 2010 book by Robert Bauval & Thomas G. Brophy, Black Genesis. In it, they argue that the dark-skinned creators of Nabta Playa were the ancestors of the Egyptian culture, who migrated eastward as the Sahara dried up. The book has been reviewed favourably by Bruce Jeffries-Fox(b) and very critically by Jason Colavito in four parts(c-f) . This was followed in 2012 by another book from Bauval & Brophy, Imhotep the African, in which they explore further the development of ancient Egypt, particularly the part played by Imhotep.
Jean Deruelle (1915-2001) was a French mining engineer, who identified Northern Europe as the cradle of technological development, preceding the great civilisations of the Middle East. He contends that the advances of Northern Europe diffused to the southern nations of the Mediterranean. Deruelle identified Imhotep as an Atlantean immigrant to Egypt, where he contributed to the advances of its civilisation during the 3rd millennium BC and became its chief architect.
More specifically, he places Atlantis in the North Sea, on the Dogger Bank, which is a shoal around 100 km off the northeast coast of England. He has written at least two books on the subject of Atlantis.
A number of maps illustrating his theory are available on a French forum(a).
Fortunately, an English translation of his theory is available on the de Grazia website(b).
*Deruelle imaginatively proposed that great plain of Atlantis lay to the east of the Dogger Bank, stretching as far as what is now Denmark. Plato described the plain being surrounded by a huge ditch. Then Deruelle, with a flash of ingenuity claimed that it was not a ditch but instead was a dyke, designed to hold back the slowing advancing waters of the North Sea that were being fed by deglaciation. He endeavoured to reinforce this claim with the proposal that the Greek word for ditch, ‘taphros’ can also be used for dyke. This interpretation seems possible according to W.K. Pritchett, the distinguished historian [1622.52.5].*