I have just watched a documentary on ARTE about Stonehenge.

A team of archeologists reconstituted the stone circles in real-size painted polystyrene designed to look exactly like the original. They placed them in the plain of Salisbury, about 15km from the original, with the same alignment to the sun minus 1 degree, as the sun rise at the solstices has shifted by 1 degree since the heydays of Stonehenge 4000 years ago.

The documentary showed simulations of the sunrise at the summer solistice and sunset at the winter solstice, as well as a particular position of the moon above the horizon that only happened every 19 years. Everything was in perfect alignment.

The Construction

The site itself has been used for 10,000 years, and the stone circles probably replaced older wooden ones.

Here is some information I found on Wikipedia about the construction of Stonehenge :

Quote Originally Posted by Wikipedia
Stonehenge 1 probably needed around 11,000 man-hours (or 460 man-days) of work, Stonehenge 2 around 360,000 (15,000 man-days or 41 years) and the various parts of Stonehenge 3 may have involved up to 1.75 million hours (73 000 days or 200 years) of work. The working of the stones is estimated to have required around 20 million hours (830 000 days or 2300 years) of work using the primitive tools available at the time.
However, the documentary explained that it could have been possible for 32 men to move even the heaviest stone in just 3 months from their site of origin 30km away (about 1km every 3 days). The technique involves placing the lintel on logs then insert wooden poles like boat oars on each side and "row" (just like on water). The team reproduced the experience with a concrete lintel the same weight as those of Stonehenge, and asked a dozen people to "row", and it did move relatively easily.

They also managed to raise to the 4m long lintels of 25 tonnes with the same technique, simply by inserting logs when the lintel is raised by the lateral "oars" (used as levers), thus creating a kind of scaffolding. Another wooden scaffolding would have been used for the people to hold the wooden levers. In one hour the team (of about 12 people) raised the 25-tonne concrete lintel by 90cm. Once the wood for the levers and scaffolding was ready, it would have taken about 5 hours for ancient Britons to raise those lintels by 4 meter on top of the standing stones.

This was for the lintels. I made a quick mental calculation of the time it would have taken with the same technique for the 80 standing stones of sarsen from the Preseli Hills, 250 km away in Wales. The answer is 750 days, or about 2 years. This is a far cry from the 200 years mentioned in Wikipedia. Like with the Great Pyramids of Egypt which are most likely made of concrete blocks poured on location (see article), more ingenuous techniques than previously thought could save a lot of time to the estimated making of Stonehenge.

I also seriously doubt that it would have taken "2300 years" for the working of the stones itself. First of all, they are pretty rough in cut. Secondly, it could very well have been that stones of adequate size or shape already existed in the nature, and that it is why they decided to being them from so far away (250 km for the biggest standing stones !).


The Function

We are left to guess what Stonehenge was really used for. It is very likely that it was a ceremonial site. The documentary insisted on the importance of the Winter Solstice, and the fact that the monument was made of stone and not wood, like the nearby Woodhenge, to which it was connected by an "avenue" and the River Avon.

They hinted that stone was used in funerary monuments in most cultures worldwide, so that Stonehenge could be dedicated to the departed, while Woodhenge would be for the living. The journey from Woodhenge to Stonehenge would symbolise the passage from life to death. This is further supported by the Winter Solstice alignment, which would be for celebrating ritual for the deaths on the shortest day of the year, maybe a way to conduct the departed souls to the other world, which would liken them to the function of Egyptian pyramids.

It is very likely in my eyes that Ancient Britons 4,000 years ago had similar metaphysical beliefs to those of their contemporary Egyptians. After all, didn't humans at that time in those two regions just enter the agricultural age ?

What bothers me with this theory is that Stonehenge used to be made of wood originally, and was only progressively replaced by stones. This kills off the contrast with Woodhenge for its first centuries (millenia ?) of existence.

Role in agriculture

The experts have also noticed that the stone alignment was a convenient indicator of the seasons, through the movement of the sun. Stonehenge could thus have acted as a giant season sundial. Contrarily to tropical Egypt where seasons rely more on the flood of the Nile than on temperature and sunlight, argicultural life in Britain heavily depended on the seasons. It was vital not to plant the crops to early or too late in the year, which is why such a "seasonal clock" could have been remarkably useful.

Acoustics

The documentary mentioned the amazing acoustic of the reconstituted monument. Sounds are reverberated toward the centre of the circle, so that human voices wouldn't be audible from the outside, while amplified inside. Walking around the complex would give alternances of heightened or faded sounds. This could also have had a role in ceremonies.

It is startling to think that people already had such a mastery of acoustics over 4000 years ago. But it could be just a coincidence (the team didn't seem to expect this result before completing the polystyrene reconstruction). On the other hand, ancient Greeks knew what they were doing when they built their theatres 1500 years later (quite a time gap though).

Beyond the stones

Personally, I thought (wild guess) that a wooden structure could have completed the stone one, thus making a sort of huge building (palace, super-temple ?) for the local king. It needs to be calculated, but couldn't there be logs long enough to make a sort of flooring on top of the lintels ? This does not contradict the possibility of the site being used as a sort of temple. On the contrary, instead of just a "ritual site" it would really have become a temple, with a roof. Again, this is just a wild guess.