Gulf of Tonkin
Derek Cunningham is the author of a website(a) with an extensive amount of material devoted to archaeoastronomy. His core idea is that there existed in ancient times a World Map based on the the Cygnus constellation, echoing some of Andrew Collins’ work.
Included on his site is an article that somehow links a painting, allegedly a map, in the Lascaux Cave with a location in Viet Nam’s Gulf of Tonkin, which Cunningham describes as having “dimensions and geographical features similar to Plato’s description of Atlantis.” He later adds that “of all the various locations proposed, this is the only site that appears consistent with Plato’s description.” As a layman I found the article and the site in general, totally confusing, forcing me to lie down in a darkened room.
However, I cannot deny that Cunningham has put a lot of work into his site and he does have fans(b), but his ideas are too ‘way out’ for me.
His most recent ‘discoveries’(c) include an association of the layout of the Stonehenge complex with the Milky Way!
He later extended his studies to the remarkable terraced walls of Sacsayhuamán near Cuzco in Peru. In a 2014 illustrated article in Popular Archaeology online magazine, he claimed that the angles of the adjoining ends or sides of the irregular yet tightly fitting stones have astronomical significance!
Cunningham, has now turned his attention to angles inscribed at ancient sites, which he now claims can be associated with astronomical features and events. His extensive article(e) on the Migration and Diffusion website deals with a great many numbers that I shall leave others to evaluate.