Considering the ancients were keen to line up their site with stars in the night sky, it would make sense that they could have been used to single out certain stars for observation.
It is interesting that Dolmens can be found throughout Europe, Northen Africa, and even in parts of Asia, meaning that it was a large world-wide idea. It makes you wonder how and why an idea was adopted by many different people across the planet.
It can say that was the only civilization that had a certain knowledge and technology, but later was divided into different Nations.
I like to think that ancient civilisations very highly global compaired to how we think of them. They were clearly sophisticated and organised, so it would not be an "out there" thought that suggests they may have had global trade and maybe even a forgotten empire that stretches further than one can imagine