An unexpected discovery may change the way we think about the history of Stonehenge in the UK. Questions have arisen about the origin of the Altar Stone, which is considered one of the central objects of the megalith, reports The Vice.

A team of researchers from the University of Aberystwyth found out that the geological composition of this stone is different from others. This means that its origin may not be what was previously thought.

The altar stone is 16 feet long and is the largest of the “blue stones” that form the inner circle of Stonehenge. For the past century, researchers have speculated that it came from a basin in the Minedd Preseli region of western Wales, which is the source of the site’s other blue stones.

However, it turned out that this stone has a special geological composition, including a high barium content. This distinguishes it from other samples of the historical monument.

“It might be that the Altar Stone arrived later and if so might have been brought from another area than Wales and also possibly by different people,” said geologist Richard Bevins in this regard.

As you know, the legendary Stonehenge is located on a hilly wasteland near the city of Salisbury in the UK. The object consists of several circles of giant stones. According to some theories, people were not involved in its construction, and the boulders were “brought” by a glacier.