Stonehenge mystery is SOLVED after 5,000 years - as scientists finally crack why the mysterious monument was built

Why the mighty Stonehenge was built around 5,000 years ago has long been one of the great mysteries.  

But according to a new study, we may finally have an answer. 

Scientists say Wiltshire's famous stone circle was built as a symbol of unification between three distinct corners of Britain.  

We know that Stonehenge's rocky slabs were transported as far afield from southwest Wales and northeast Scotland. 

So the scientists, from University College London and Aberystwyth University, theorise that Scottish and Welsh people brought their own local stones down to Wilshire as a well-meaning contribution to assembling the structure.

In that sense, it represented a powerful – and very early – symbol of British unity. 

Stonehenge's builders had attempted to establish 'political unification and shared identity across much or even all of Britain', the authors say in their paper, published in Archaeology International.  

They add: 'Bringing together these extraordinary and alien rocks... symbolised and embodied far and distant communities within a complex material.

'[Stonehenge was a] monumental expression of unity between people, land, ancestors and the heavens.' 

In the paper, the researchers say Stonehenge’s long-distance links add weight to the theory that the Neolithic monument may have had some unifying purpose in ancient Britain, to go with its symbolic value. 

'The fact that all of its stones originated from distant regions, making it unique among over 900 stone circles in Britain, suggests that the stone circle may have had a political as well as a religious purpose,' said lead author Professor Mike Parker Pearson at UCL's Institute of Archaeology. 

'[It was] a monument of unification for the peoples of Britain, celebrating their eternal links with their ancestors and the cosmos.' 

Even though England, Scotland and Wales did not exist as concepts when Stonehenge was built 5,000-odd years ago, we know the structure is indeed representative of all three countries.

Stonehenge is famous for its great sandstone slabs, known as sarsens, which were sourced locally – likely hauled from West Woods in Wiltshire, around 15 miles north. 

But in addition to the tall Sarsen stones that make up Stonehenge's distinctive appearance, the world-famous site is also home to around 80 'bluestones' – smaller stones that have a bluish tinge when freshly broken or when wet. 

Among Stonehenge experts, it is generally agreed the bluestones came from Craig Rhos-y-Felin in the Preseli Hills of south-west Wales (although how exactly they got to Wiltshire is hotly debated). 

However, the Altar Stone, the largest bluestone at the centre of Stonehenge, actually came from northern Scotland – up to 1,000km (621 miles) away, scientists revealed earlier this year. 

Lying flat at the heart of Stonehenge, the six-tonne, five-metre-long rectangular Altar Stone is a grey-green sandstone, far bigger and different in its composition from the other bluestones.

At the time, the research team (which included two authors of this new paper) analysed the age and chemistry of minerals from fragments of the Altar Stone.

They found a remarkable similarity with the Old Red Sandstone of the Orcadian Basin in northeast Scotland. 

The team concluded 'with 95 per cent accuracy' that the stone came from this area – which encompasses parts of Inverness, Thurso, Orkney and parts of Shetland – although they've since ruled out Orkney as the location. 

In this new follow-up paper, the team say the Altar Stone was brought by the Neolithic people of northern Scotland as a contribution or gift to the southerners. 

'[This was] perhaps to cement an alliance or to take part in the extraordinary long-distance collaboration that building Stonehenge represented and embodied,' the authors say. 

Likewise, the bluestones could have been transported by people from the Preseli Hills of south-west Wales as their own contribution – illustrating 'a political unification or a sacred peace'. 

This follow-up paper now identifies Stonehenge construction 'as a monument of island-wide unification, embodied in part through the distant and diverse origins of its stones'. 

'Unusually strong similarities in house floor layouts between Late Neolithic houses in Orkney and the Durrington Walls settlement near Stonehenge also provide evidence of close connections between Salisbury Plain and northern Scotland,' the team say. 

Stonehenge was used as a cremation cemetery for mostly adult men and women for around five centuries in its early history. 

Nearly half the people buried at Stonehenge had lived somewhere other than Salisbury Plain, the experts say – showing people historically flocked there from afar.  

'The similarities in architecture and material culture between the Stonehenge area and northern Scotland now make more sense,' added Professor Pearson. 

'It’s helped to solve the puzzle of why these distant places had more in common than we might have once thought.' 

The new research comes a day before the winter solstice – the shortest day of the year where thousands of people flock to Stonehenge. 

During the winter solstice, the setting sun dips below the horizon over the middle of the Altar Stone and between the two largest upright stones (one of which is now fallen). 

For thousands of years, it's thought people gathered at Stonehenge at both midsummer and midwinter solstices to conduct rituals and ceremonies relating to the changing seasons, the sun and the sky. 

During the winter, Neolithic people also feasted close to Stonehenge at the nearby settlement village of Durrington Walls. 

Largely because it's a whopping 5,000 years old, the origins of Stonehenge, including why and how it was built, are still a source of frenzied debate.

Professor Timothy Darvill, an archaeologist at Bournemouth University who passed away earlier this year, said Stonehenge served as an ancient solar calendar, helping people track the days of the year.

The British researcher said the sarsens each represented a single day in a month, making the entire site a huge time-keeping device.

Other theories include that it was a cult centre for healing, a temple, a place where ancestors were worshipped or even a graveyard.