Your guide to Stonehenge, plus 12 fascinating facts you might not know

Follow the links below to jump to each section:

• Why was Stonehenge built?
• How old is Stonehenge?
• How many stones were used to build Stonehenge?
• Where do the stones for Stonehenge come from?
• What have been the biggest threats to Stonehenge?
• 12 fascinating facts about Stonehenge

In 2018, historian Miles Russell – who was part of a team excavating within the central uprights of Stonehenge in the first archaeological investigation there for 70 years – took on the top questions about Stonehenge for BBC History Revealed…

Q: Why was Stonehenge built?

Over the years there have been many suggestions as to why the stones were set up on Salisbury Plain. The earliest interpretation was provided by Geoffrey of Monmouth who, in 1136, suggested that the stones had been erected as a memorial to commemorate British leaders treacherously murdered by their Saxon foes in the years immediately following the end of Roman Britain. The stones were, Geoffrey wrote, part of an Irish stone circle, called the Giant's Dance, which were brought to Salisbury Plain under the direction of the wizard Merlin.

Geoffrey of Monmouth suggested that the stones had been erected as a memorial to commemorate murdered British leaders

The first detailed study of the stones, conducted by the architect Inigo Jones early in the 1620s, concluded that the monument could not have been the work of the primitive Britons who "squatted in caves" and lived "on milk, roots and fruits", but had to have been designed by the Romans, probably being a temple dedicated to Apollo.

In 1740, antiquarian William Stukeley published his history of Stonehenge, subtitled 'A temple restored to the British druids'. Stukeley suggested that the circle had been built by a pre-Roman Celtic priesthood of Sun-worshippers descended from the Phoenicians, who had travelled to Britain from the eastern Mediterranean "before the time of Abraham".

The first official custodian of Stonehenge, Henry Browne, wrote and privately published the first guidebook, which he sold direct to visitors in 1823. Browne's theories, however, were shaped by the Old Testament; he postulated that the structure was antediluvian, meaning it was one of the few monuments that had survived the Biblical flood.

A popular theory within the 1960s counter-culture was that Stonehenge was an advanced form of computer or calculating device. In his 1965 book Stonehenge Decoded, astronomer Gerald Hawkins suggests that the stones had been positioned to accurately predict major astronomical events. Many of Hawkins' ideas concerning Stonehenge as prehistoric observatory have now been dismissed, although the summer and winter equinoxes remain popular times of the year to visit the monument today.

• Your guide to Britain’s prehistoric stone circles
  

Q: How old is Stonehenge?

Damaged and distant though it undoubtedly is, Stonehenge remains awe inspiring, especially when one considers it was put together 4,500 years ago by a pre-industrial farming society using tools made of bone and stone.

As far as can be determined, work at the site began somewhere after 3000 BC, with the construction of a circular, externally ditched earthwork enclosure. Quite why this particular part of Salisbury Plain was considered important, we will never know, but the new enclosure, which contained cremation burials and settings for timber and stone uprights, including a number of bluestones from Wales, possibly acted as a form of communal cemetery.

A major change came at around 2500 BC with the addition of a horseshoe of sarsen (sandstone) trilithons surrounded by an outer circle of sarsens, all joined with lintels. The bluestones were, at this time, repositioned in a double circle between the larger sarsen settings. The Station Stones, a series of sarsens placed within the inner edge of the surrounding earthwork, may also belong to this phase, as indeed does the rearrangement of stones within the main, northeast-facing entrance to the enclosure.

Damaged and distant though it undoubtedly is, Stonehenge remains awe inspiring

The third stage of modification came between 2400 and 2300 BC with the construction of the Avenue, the recutting of the main enclosure ditch, and the reorganisation of the entrance stones. Around 2200 BC, the bluestone circle was disassembled and rearranged into two oval settings, one inside the horseshoe of sarsens and one between this and the outer sarsen uprights.

By 1800 BC, the stones were being broken and carvings were being etched into the sarsens. At some point in the late- or post-Roman period, during the 4th or 5th century AD, the bluestones were again modified, but the full extent of this alteration is unknown.

The first attempt to resolve the date of Stonehenge occurred in the 1620s during an excavation commissioned by the Duke of Buckingham. Unfortunately we know little about the work, other than it exposed at least two large pits, together with “stagges hornes and bulls hornes” and “pieces of armour eaten out with rust”. None of these finds survive. Further exploration took place in the early 19th century, work which may have contributed to the overall instability of the stones. On New Year’s Eve 1900, part of the outer circle of sarsen stones collapsed, taking down a lintel with it.

• Listen | Mike Pitts considers how and why the monument was created, more than 4,000 years ago

Concerns about the security of the stones led to a renewed phase of excavation and stone straightening. Between 1919 and 1926, excavations centred on the site’s southeastern quadrant. Another campaign of excavation took between 1950 and 1964, together with a programme of stabilisation, repair and stone re-erection. Although reconstruction of the monument has helped ensure the long-term survival of Stonehenge, the results of these excavations were not published until 1995.

In 2008, two smaller, targeted archaeological excavations took place within the circle. The first (which I took part in), designed to investigate the date, nature and settings of the internal smaller stones, recovered significant evidence for late- and post-Roman use of the monument. The second, which focused on retrieving cremation burials from the earliest phase of the site, demonstrated that men, women and children had all been buried there between 3000 and 2500 BC. Research published in August 2018 revealed that some of the prehistoric cremations recovered were of individuals who were not local to the monument, possibly – although this is yet to be confirmed – originating from western Wales, Ireland or northern Scotland

Archaeological investigation, limited although it has been to date, has proved helpful in establishing a building chronology for Stonehenge. No single phase of the monument, it is fair to say, was probably ever completed; it is likely that it was an ongoing building project throughout much of its existence.

Q: How many stones were used to build Stonehenge?

We don’t know for sure, as certain phases of the monument may never actually have been completed. If we assume that the outer ring of sarsens was finished, then it would have contained 30 uprights and 30 lintels. Add to this the five trilithons in the central horseshoe, that gives us 75 sarsens in total. Beyond the centre there are four additional sarsens standing today, but there are recorded holes, for those moved or taken away, for at least another ten.

In addition to the sarsens, there is the large sandstone monolith (now fallen) known as the Altar Stone, and an unknown number of bluestones. The outer circle of bluestones may originally have contained 60 uprights, although there is only certain evidence for 28 and, of those, only seven are still standing. The inner bluestone horseshoe may have contained 19, of which only six still stand. A conservative guess would suggest something in the region of 169 stones on the site at any one time.

Q:Where do the stones for Stonehenge come from?

Geologically speaking, two discrete sources can be identified for the stones used in the construction of Stonehenge. The most impressive uprights, the sarsens, were sourced locally, possibly from somewhere near the Marlborough Downs, approximately 20 miles to the north. Here, naturally occurring sarsen can still be found and, although none are today as big as those recorded from Stonehenge, it was probably from here that they were originally dug out of the ground – quite an effort considering most weigh between 30 and 40 tonnes. [In July 2020, archaeologists confirmed that the origin of the giant sarsen stones at Stonehenge has finally been discovered, pinpointing the source of the stones to an area 15 miles (25km) north of the site near Marlborough].

From Marlborough, it is likely that the roughly shaped blocks were transported across the undulating landscape of Wiltshire to their resting place on Salisbury Plain. Quite how this was achieved, given the technology and resources available to Neolithic people, continues to perplex, intrigue and annoy academics to this day.

Two discrete sources can be identified for the stones used in the construction of Stonehenge

The smaller bluestone (dolerite and rhyolite) pillars are of volcanic and igneous origin. The most likely source of them are outcrops in the Preseli Hills in Pembrokeshire, 155 miles to the west, where recent archaeological work suggests the presence of prehistoric quarries. It is possible that the stones were cut direct to order; alternatively, they may have been part of a Welsh stone circle, moved wholesale to Salisbury Plain.

Q: What have been the biggest threats to Stonehenge?

The military | Salisbury Plain has been a training ground for more than a century. Today the army is mindful of the monument, but it was not always so. Mine tests during World War I, together with tank and artillery firing practice, caused some stones to move and fracture. Then came the arrival of the Royal Flying Corps in 1917, whose aircraft skimmed the tops of the lintels as they came in to land.

Hands-on tourists | Until the late 19th century, visitors regularly chipped off pieces to take home and engraved their initials into the monument. Campers set up within the circle, digging fire pits that undermined the stability of the stones.

• In pictures: Stonehenge tourism

Human-made eyesores | Unrestricted access to the interior of Stonehenge in the mid-20th century resulted in significant erosion and an increase in picnic-related litter. Fences, paths and custodians’ huts helped to reduce the damage, but added unsightly new elements. The removal of a car park and the huts, and moving the visitor centre, has started to bring a more ‘natural’ feel to the site.

Festivalgoers | The Stonehenge Free Festival, timed to coincide with the summer solstice, brought thousands to Salisbury Plain in the 1970s and 1980s, causing significant damage to the landscape. It came to and end in 1985 after the so-called Battle of the Beanfield, in which riot police prevented travellers from entering Stonehenge to set up the festival.

Increasing traffic | To the north, the A344 passed within a few metres of the site, whilst the A303 – a main route between London and several popular holiday destinations – is close by to the south. Together, they generated ground vibration. The removal of the A344 has reduced the threat, although the A303 remains.

12 fascinating facts about Stonehenge

Here are 12 of the most important quick-fire facts about Stonehenge and its mysterious origins – from the story of its construction to its fascinating links with astronomy, and why earthworms once posed the biggest threat to its future…

Stonehenge was built in several stages

Built in several stages, Stonehenge began about 5,000 years ago as a simple earthwork enclosure where prehistoric people buried their cremated dead. The stone circle was erected in the centre of the monument in the late Neolithic period, around 2500 BC.

It includes two different types of stone

Two types of stone are used at Stonehenge: the larger sarsens, and the smaller bluestones. Most archaeologists believe that the sarsens were brought from Marlborough Downs (20 miles away), while the bluestones came from the Preseli Hills in south-west Wales (140 miles). The exact method is not known, but the stones were probably hauled across the land or carried to the site using water networks.

It's not a henge

There are many henges in Britain, but you can’t count Stonehenge among them. The term describes a raised earthwork with an internal ditch; Stonehenge’s ditch is outside its earthwork, meaning it isn’t a true henge. Avebury, several miles to the north, is probably the most famous real henge.

Stonehenge extends underground

The sarsen stones at Stonehenge may look big (they are) but around a quarter of their bulk is buried underground for support. Stone 56, the largest surviving upright of the inner sarsen trilithon, stands 6.58 metres above ground, with 2.13 metres out of sight, giving it an overall height of 8.71 metres.

The earliest depiction of Stonehenge is rectangular

The earliest depiction of Stonehenge appears in the Scala Mundi (Chronicle of the World), compiled around 1340. The monument is drawn rather unrealistically, appearing rectangular (rather than circular) in plan.

There were originally two 'entrances'

There were originally only two entrances to the enclosure, English Heritage explains – a wide one to the north east, and a smaller one on the southern side. Today there are many more gaps – this is mainly the result of later tracks that once crossed the monument.

Stonehenge includes a circle of 56 pits

A circle of 56 pits, known as the Aubrey Holes (named after John Aubrey, who identified them in 1666), sits inside the enclosure. Its purpose remains unknown, but some believe the pits once held stones or posts.

It was built at a time of "great change"

The stone settings at Stonehenge were built at a time of “great change in prehistory,” says English Heritage, “just as new styles of ‘Beaker’ pottery and the knowledge of metalworking, together with a transition to the burial of individuals with grave goods, were arriving from Europe. From about 2400 BC, well furnished Beaker graves such as that of the Amesbury Arche are found nearby”.

Roman artefacts have been found at the site

Roman pottery, stone, metal items and coins have been found during various excavations at Stonehenge. An English Heritage report in 2010 said that considerably fewer medieval artefacts have been discovered, which suggests the site was used more sporadically during the period.

Stonehenge has fascinating links with astronomy

Stonehenge has a long relationship with astronomers, the 2010 English Heritage report explains. In 1720, Dr Halley used magnetic deviation and the position of the rising sun to estimate the age of Stonehenge. He concluded the date was 460 BC. And, in 1771, John Smith mused that the estimated total of 30 sarsen stones multiplied by 12 astrological signs equalled 360 days of the year, while the inner circle represented the lunar month.

Charles Darwin discovered why the stones were sinking

In the 1880s, after carrying out some of the first scientifically recorded excavations at the site, Charles Darwin concluded that earthworms were largely to blame for the Stonehenge stones sinking through the soil.

Stonehenge was in a sorry state by the 20th century

By the beginning of the 20th century there had been more than 10 recorded excavations, and the site was considered to be in a “sorry state”, says English Heritage – several sarsens were leaning. Consequently the Society of Antiquaries lobbied the site’s owner, Sir Edmond Antrobus, and offered to assist with conservation.

Find out more about how to visit Stonehenge and book tickets with English Heritage

This article was originally published by HistoryExtra in September 2014 and updated with information from BBC History Revealed in July 2020