1) Aliens with precognition perhaps (who could foresee the measuring system of metrics today?)

2) Time travelers who brought the concept back?

3) I largely (80%) agree with Hermione's dissection.


However, I'd like to point out that, cherry picked evidence & goalpasts notwithstanding, the table presents a singular core of evidence for his theory.

He then uses that theory to predict logical (according to his theory) places to examine for ruins.

It's a logical test of his (admittedly speculative) hypothesis regarding the spacing of these sites. Now, if he can get to those predicted sites *and find something* then he might have something.

Of course, he will *also* have to find a better evidenced theory for the cherrypicked pieces of evidence... ie why some sites on the table and ignore others? What binds these sites, founded across such aeons from each other, together to the exclusion of other sites that surely lay in between and not on such round KM intervals?

OTOH the whole concept rather reminds me of the speculations on crater impacts occurring near each other in geometrically precise patterns...