New evidence has emerged suggesting part of Stonehenge was in place long before humans arrived.
Archaeologists have tried to figure out why the rock formation was set up where it is, seemingly randomly-placed in the middle of the Salisbury Plain in England, for hundreds of years. It has long been assumed the rocks, a form of hard sandstone known as sarsen, do not occur naturally on the site.
Now, one of the only archaeologists to have ever excavated on the site thinks otherwise.
In an article published in the British Archaeological journal, Mike Pitts says the two largest sarsen stones were likely there first, and the other blue stones later set up around them by humans.
The largest rock, the heel stone, weighs around 60 tonnes. In the '70s, Mr Pitts discovered a six-metre-wide hole next to the heel stone, now filled in, which he believes was the original site of the boulder.
If he's right it would dispel the theory the rocks were dragged 32km by humans, which has long-remained a mystery in itself.
"The assumption used to be that all sarsens at Stonehenge had come from the Marlborough Downs," Mr Pitts wrote.
"The idea has since been growing that some may be local and the heel stone came out of that big pit. If you are going to move something that large you would have to dress it before you move it to get rid of some of the bulk.
"That suggests it has not been moved very far. It makes sense that the heel stone has always been more or less where it is now, half-buried."
Mr Pitts believes the rocks' alignment with sunrise and sunset was a coincidence.