My understanding, which could be in error of course, is that humans were capable of complex construction well before 6,000 years ago, and that man was
not merely what we think of today as cavemen (in terms of raw intelligence at least) by that time.
As I understand it, until roughly 50,000 years ago, there was a high degree of homogeneity between disparate primitive cultures. Around that time, we
began to create cave paintings, and used tools and tactics to a higher degree, and with greater novelty and variety. By roughly 40,000 years ago human
beings had roughly the same cognitive capacity as today. Only their tools, resources, and knowledge differed from ours.
Even from roughly 40,000 to roughly 13,000 years ago, the distinctions between various cultures appear to have been relatively minor. After around
13,000 years ago however (and possibly earlier,) sedentary settlements began to spring up.
Roughly 11,500 Near the Euphrates, a temple-like structure existed in what is now southeastern Turkey. Its earliest form consisted of monolithic
pillars connected by roughly built walls, which formed circular or ovalular shaped structures. Some of these pillars featured carved reliefs of
animals and other symbols. 11,000 to 10,000 years ago, this temple was expanded with the construction of adjacent rectangular rooms with floors of
Around 12,000 to 10,000 years ago, agriculture is believed to have developed in the fertile crescent. Jericho was founded shortly thereafter.
By 7,000 to 6,000 years ago, the Proto-indo-European culture had devised what may be the oldest cosmology that we have a record of; a religion
including a caste system with priests, and other clerics overseeing lower warrior/hunter and peasant or animal husband castes.
So we were already thinking, acting, and abstracting in all of the ways that would necessitate the construction of temples or other sacred structures
well before 6,000 years ago, according to what we know thus far. (Which could, as recently elucidated by the possible discovery of modern human
remains hundreds of thousands of years older than previously thought, be completely turned on its head at any time of course, for all we know.)
That said, I have always been fascinated by the concept of ley lines, and I believe anything is possible when it comes to a history we have little
direct access to due to time and decay. Furthermore, new research suggests the possibility that our entire carbon dating method may be wholly
unreliable and not as precise as we long believed.
So as usual I'm left with the same question I always am: what do we really know for certain?