http://www.bbc.com/news/uk-england-wiltshire-34156673
And Stonehenge is far from being the only examplar of its kind. There's a big one in Scotland:
https://en.wikipedia.org/wiki/Callanish_Stones
And another in Brittany:
https://en.wikipedia.org/wiki/Carnac_stones
It seems like back in the Neolithic, there must have some kind of pan-euroasian craze for menhir based construction.
Gobleki Tepeh predates known agriculture and permanent settlements. It really is a singular site, with genuine mystery.
Wooly Mammoths went extinct 4500 years ago.
Ref: https://persquaremile.com/2011/08/17/hunter-gatherer-populat...
I don't think you'd need 10,000 people to construct a structure like Stonehenge, especially when you consider that these were built over vast intervals of time (hundreds of years per structure, thousands for the entire site).
There are other structures that seem to have been built by hunter-gatherers. Stonehenge comes to mind. The construction dates of Stonehenge aligns with the absolute dates of civilizations elsewhere in the world, but in the British isles it was still a time of hunter gatherers.
There is also much archaeological evidence for large, permanent "meeting point" structures built with wood columns and dirt fortifications. What makes Gobekli Tepe interesting is that it is stone (albeit a very soft stone that didn't need complex tools to work with) and therefore we have more than just holes in the ground and oddly shaped hills to look at.