After decades of debate, a new study has revealed the epic journey that the Altar Stone, a six-ton sandstone block, took to arrive at the center of Stonehenge.

It is impossible to count how many studies have been written about Stonehenge, as it remains one of the most heavily investigated archaeological sites in the world.

Researchers have spent 300 years debating its exact purpose, suggesting various theories, including that it served as a cremation cemetery, a sacred ceremonial temple, or an astronomical calendar.

While the archaeological site remains somewhat mysterious, this new study has resolved a long-standing question about how the central Altar Stone was transported to Stonehenge. After all, the massive stone measures 16 feet long and 3.3 feet wide, and it weighs 13,228 pounds.

Neolithic peoples, with limited technology, would have had to travel impressive distances to move such a colossal megalith over 435 miles, as researchers determined that the stone originated from the Orcadian Basin in northeastern Scotland. But that is still not specific enough for archaeologists.

The exact location of the stone within this large basin remains unresolved, as does the method of transport. Without knowing the exact origin, archaeologists cannot retrace the stone’s journey with the degree of precision they would like, but “you gotta start somewhere.”

Hypotheses have ranged from human transport by land and sea to glacial transport—with the glacial theory having generated the most buzz. But then again, everyone has theories about Stonehenge.

The new study aimed to determine once and for all where the stone came from and how it reached one of the most famous and mysterious sites in the world.

The epic journey of Altar Stone

To uncover the secrets of the Altar Stone, researchers combined sandstone provenance analysis—also known as mineral grain dating—with ice flow modeling to identify potential sources and transport pathways.

The modeling revealed that glaciers may have transported rocks part of the way during the last Ice Age, potentially as far as the Dogger Bank in the North Sea, but not into southern England.

The stone was therefore not carried by ice, but rather through “a deliberate, carefully planned movement across a challenging and varied landscape,” according to Dr. Clarke. This means that the 13,228-pound stone was moved by humans over hundreds of miles.

Given the massive undertaking, archaeologists proposed that “the stone was likely moved in stages, potentially combining overland hauling with river or coastal transport where possible.”

Imagining a group of Neolithic individuals hauling an impossibly heavy and awkward stone across uneven, difficult terrain and over bodies of water for an untold amount of time is certainly inspiring.

Altar Stone = manpower

The latest study builds on earlier findings that ruled out glaciers as the sole means of transport, supporting the conclusion that a group of Neolithic individuals ventured out into the wild unknown to source and transport this stone using nothing but human power.

“Transporting a stone of this size over such a long distance would have required careful planning, coordination, and an in-depth understanding of the landscape—not to mention tremendous determination,” says lead author Dr. Anthony Clarke in a press release.

Dr. Clarke noted that this level of organization and cooperation among Neolithic communities had not previously been fully realized or appreciated. Scientists are going to great lengths to retrace the stone’s steps in this research. Future studies will aim to pinpoint the Altar Stone’s exact location of origin within the Orcadian Basin and map its transport journey in exquisite detail.

Perhaps this story will even inspire a prehistoric comedy. The study is available in the Journal of Quaternary Science.

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