25,000 yrs ago how do you mobilize hunter gatherers who spend the whole day to hunt food to work day and night to create an engineering masterpiece?
AFAIK nothing on that scale was ever made by hunter-gatherers, nor has anything like that been dated to 25K years ago. This place is interesting:
Göbekli Tepe - Wikipedia
(about 12K years old)
* The Egyptians were building quite big things 5000+ years ago, but they were already well organized then.
* Gunung Padang has been dated to Roman times (**)
* Nan Madol was started in Viking times (**)
(**) Those two were built at a lower tech level than the comparisons (Roman, Viking) OFC. But much of the world was
well past simple hunter-gather societies by then.
Note that columnar basalt is a
very convenient building material, ideal for moderately organized low-tech societies.
There's no need for large-scale stone shaping because its natural cross-section is hexagonal, with nice flat sides.
Any group with easy access to a source if it would use it for construction, starting with simple structures (dwellings, storage, etc), and scale up as they developed skills and techniques.
People
always take advantage of available, exploitable resources. It would be unnatural if they
didn't.
And how did they erect such massive stones in elevated positions? again coconut fibre is a rather lazy method to explain this away
You're underestimating the quality of coir rope, and possibly the ease with which it can be made.
And perhaps missing something equally important: rope is
extremely scalable, because it's easy to share a large load across many separate ropes. Coir rope was use for rigging in medium-tech wooden ships for centuries (this is an indication of reliability and strength vs size).
The site is composed of up to 50,000 hexagonal columnar basalt blocks, some of which weigh around 650 pounds ( 0.3 tonnes) and others as much as 880 pounds (0.4space 0.4 tonnes).
Given access to wood and stone axes (or better) to shape it, raising columnar stones at these weights would be easy, and while good rope would be handy (and they probably had access to it), it wouldn't be necessary.
Not by building a crane of course: You lift them with levers.
Get a 3-meter-long lever under one end (dig a small hole for the first lift, lift it 20 cm or so, and put a block under it. Do the same at the other end.
Repeat.
A gang of 4 guys could do this at a few minutes per vertical meter.
Pieces of the right kind of wood the size of railway sleepers are easily enough to hold up a multi-tonne object, and you can build the supports quite high.
Modern jacks are easier of course, but wood is actually a great material for the supports.
I've done this (as past of a project that lifted and moved a building about the weight of a 3/4 bedroom house).
We used modern lifting and horizontal jacks of course, but the supports were actual old railway sleepers.
We lifted it high enough to get a suitable truck underneath it for transport, so perhaps 1.5 meters.
The building was somewhere between 5 and 20 tonnes (we needed to know to get a big enough truck, but it was a very long time ago and I've forgotten - probably low double-digits).
This is why I don't see 1- or 2-tonne objects as being difficult for low-tech societies, and a few 10's of tonnes as being possible if they can get a fairly big work gang together.
Up in the hundreds of tonnes, you'd need a lot of prep and organization.
IMO 1000+ tonnes would be possible, but very difficult even for the Romans (who had metal tools, and were very well organized).
For example, at 1000 tonnes, even raising the object vertically a meter or two with a more sophisticated and scaled-up version of the leverage approach I described would be very difficult.
OFC you can lift and move really big objects by e.g. building a boat around them, constructing a big enough pool, connecting it to a canal/river, and floating the whole system.
But you'd definitely prefer to do the same thing with ten conveniently sized modules rather than one huge object.
Big stone pillars were made that way, and some have stood for thousands of years.
