From the outside — to the Bronze Age eye, at least — it must have had the awe-inspiring proportions of a cathedral.

In a windswept salt marsh, 54 wood posts, each 10ft tall, were lashed together in a tight circle. 

At the circle’s centre was an upturned tree, its roots reaching toward the heavens like branches.

All was silence and darkness —until midsummer dawned. Then, a small wooden door positioned to meet the sunrise at the solstice was flung open — and the space filled with dazzling light. 

‘It must have been a cosmic experience,’ says Dr Jennifer Wexler, a specialist in prehistoric and ancient archaeology. 

‘If you were inside the circle, it would be almost as if you were entering another realm.’

Now the mysterious structure, known as Seahenge, will go on display for the first time as part of the British Museum’s blockbuster exhibition, The World of Stonehenge, which opens in February. Seahenge, like the lost city mythical Atlantis was silently waiting for discovery for thousands of year.

Wendy George's photo of Seahenge which was discovered on Holme Beach at the time of excavation and will go on display for the first time as part of the British Museum¿s blockbuster exhibition, The World of Stonehenge, which opens in February

Wendy George’s photo of Seahenge which was discovered on Holme Beach at the time of excavation and will go on display for the first time as part of the British Museum’s blockbuster exhibition, The World of Stonehenge, which opens in February

But while Atlantis fired the imagination of dreamers and scholars, no one guessed at the existence of the curious timber circle — until a massive storm blew away the dunes on a remote Norfolk beach in 1998. 

Imagine the wonderment attained by Holme-next-the Sea’s archaeologists, when they found this enormous, Bronze Age structure more than 4,000 year old intact.

These circles have been the topic of much speculation over the years. Timber circles, however, had almost vanished, unlike Stonehenge which stood despite being abandoned after 5,000 years.

Although archaeologists have found postholes in the ground, and sporadic slivers of wood, this was what they were looking for.

‘It is a mysterious site,’ says Dr Wexler. ‘Seahenge was mystical and intriguing, perhaps a place of worship, perhaps a way for the people who built it to connect to the cosmos. But the really extraordinary thing is that it survived.’

Seahenge, like Stonehenge has helped to develop our knowledge of Bronze Age and Neolithic culture. The circle’s exact use and purpose remain a mystery, but some tantalising clues and theories have emerged.

Some think it may have been used for rituals associated with death, most probably the practice of ‘excarnation’, in which a body would be placed on the upturned tree, allowing the flesh to rot (or be eaten) from the bones, thus freeing the person’s spirit.

The Mold Gold Cape will also form part of The World of Stonehenge exhibition at the British Museum

The British Museum will exhibit The World of Stonehenge, which includes the Mold Gold Cape.

Lunula, a crescent moon shaped pendant worn in ancient Rome, believed to be from between 2400 to 2000 BC

Lunula is a pendant with a crescent moon-shaped design, worn by ancient Rome from 2400 BC to 2000 BC

‘It may also have been a place to connect with ancestors,’ says Dr Wexler. ‘We know the people who built Seahenge were farmers, closely connected to the seasons and beliefs about regeneration.’

Over the past 20 years, we have seen amazing details in archaeological research.

We know Seahenge was constructed in 2049 BC, thanks to carbon dating and the tree rings that were found in the stumps. 

It is likely that the oak in its center was an uprooted tree, which was most likely a fallen tree. The rope made of honeysuckle was used to drag it to the salt marsh.

After its discovery, Seahenge was excavated and experts who had helped save Henry VIII’s warship, the Mary Rose, advised on timber preservation. 

Part of the circle went on display in nearby King’s Lynn, but for space reasons, the whole structure could not be exhibited.

But now, for the British Museum’s new exhibition, the circle will be reconstructed in its entirety and shown alongside other wonders of the Bronze Age.

There are two styles: one made of solid gold, the other from France. They both feature elaborate solar motifs.

In addition, the famous ‘gold lozenge’ found at the burial site of the Bush Barrow chieftain, close to Stonehenge, will also be shown. 

The 1808 discovery of this circular barrow was filled with valuable items. Its occupant is thought to be a notable person, most likely a warrior, priest or chief.

The lozenge, made from gold and with inscribed intricate patterns — suggesting the person who made it had a knowledge of geometry — is believed to be the finest example of Bronze Age gold craftsmanship found in Britain.

Markings in Seahenge’s oak posts show that 51 bronze axes were used in its construction, suggesting a large community came together to create it. 

Their lives would have been simple: they lived in wattle-dumb huts, ate on open fires, and wore woollen tunics.

The Nebra Sky Disc, Germany, from around 1600 BC will be on display as part of the UK's first ever story of Stonehenge

As part of Stonehenge’s UK debut story, the Nebra Sky Disc from Germany will be displayed.

A gold flange twisted spiral torc estimated to be from between 1400BC-1100BC in Dover.

Dover: A spiral twist torc with a gold flange that was twisted in a spiral, estimated at between 1400BC and 1100BC. 

‘Occasionally as an archaeologist you find a finger mark on a [clay] pot and think, “Wow, this is the person who made this pot”,’ says Dr Wexler. 

‘You get a sense of that person. Once you can imagine the person who made them, the circle is not just a static monument, it’s dynamic and real.’

Earlier this year, in her book Stonehenge — Temple Cipher Roof, architect Sarah Ewbank outlined a theory that Stonehenge had once been a building, with the stone monoliths acting as supports for a circular, pitched roof. 

Seahenge may have used a similar roofing structure, she believes.

‘If you think of Bronze Age people being rather like us, it makes perfect sense,’ she says. 

‘For three–quarters of the year, Britain is a pretty miserable place. If it’s pouring with rain, would you want your ceremonies outside?’

She believes Bronze Age people would have been capable of creating complex structures: ‘These are people who noticed that if you got certain rocks very hot, metal came out,’ she says.

‘We like to think that because we’ve got mobile phones and things we’re much cleverer than people in the past. But we’ve built on what past people have learnt, so the person who alloyed metal to make bronze were equivalent in intelligence, I would say, to software engineers nowadays. 

The engineering behind the construction of pyramids [which were constructed around the same time as the timber circle] is as good as anything we can do today, bearing in mind we have machines.’

Dr Wexler is sceptical about the roof theory, but says: ‘The great thing about Stonehenge is there are so many theories about it we need to keep exploring.’

She chose a Geoffrey of Monmouth piece of writing for the exhibition. This cleric is credited with popularizing the legend of King Arthur. The illustration shows Merlin lifting Stonehenge into its place. Monmouth was writing during the 12th century.

‘So even 1,000 years ago they were trying to figure out what was going on at Stonehenge,’ she says. ‘They saw it as a mythological, folkloric place. This monument continues to inspire imagination.’

Seahenge, the mystery that has remained hidden for so many years but is now back to intrigue and inspire.

The World of Stonehenge is open from February 17 through July 17 at British Museum.