00:00Recently, scientists made an amazing discovery that could solve the mystery of Stonehenge.
00:05They found a hidden element at the bottom of the DNA of the Sarsen stones,
00:10the huge monoliths present on the site.
00:12This discovery could reveal why our ancestors of the Neolithic designed and built this structure.
00:18For years, scientists have been digging their heads to find out where the huge Sarsen stones come from.
00:25For a long time, they thought it came from a quarry located 25 km from the site,
00:30known as Marlborough Downs.
00:33On this site, they found minerals similar to those that make up the Sarsen stones.
00:38But in reality, things are more complex than we thought.
00:42Our understanding of the construction of Stonehenge is constantly evolving.
00:46Scientists literally have to go back in time to unravel these mysteries.
00:51Where do the stones come from? How were they transported?
00:54Why was the site built?
00:56The Stonehenge site, located in the Salisbury Plain in England,
01:00is made up of two large types of stones.
01:03There are the Sarsen stones, very heavy, and the blue stones, smaller and lighter.
01:09The Sarsen stones each weigh about 25 tons.
01:13This is equivalent to three African elephants.
01:15The heaviest Sarsen stone, called Heelstone, weighs only 30 tons.
01:21Together, the Sarsen stones form the outer circle of the structure.
01:25Inside this circle, you will find the blue stones.
01:29Their name may be a little misleading, because they are not really blue.
01:33They have a bluish tint when they have just been broken, hence their name.
01:37These small stones probably come from the hills of Presley,
01:40in the southwest of Wales, about 240 km from Stonehenge.
01:45They are a little lighter than the Sarsen stones, but still quite heavy.
01:49The Heelstone, classified among the blue stones, is the heaviest of them,
01:54with a weight of about 6 tons.
01:56Its origin is not yet known.
01:59To determine the origin of a stone, scientists must first study its composition.
02:04To do this, they check the DNA of the rock.
02:07Then, they cut the structure of the stone with the minerals present in the soil,
02:12to see if there is concordance.
02:14Most of the Sarsen stones that we see in southern England
02:18are actually made up of a type of grit known as silcrete.
02:22It is a sand hardened by underground waters for millions of years.
02:27This process is mainly produced during a period called the Paleogene,
02:31some 65 to 23 million years ago.
02:35These Sarsen stones were not formed in a single large plate,
02:40as if nature had created small stone gardens everywhere.
02:44Scientists explain that the Sarsen stones spread randomly,
02:49often in isolated areas.
02:51Over time, many of them were buried under layers of clay and grit,
02:55which contributed to their preservation.
02:58When the builders of Antiquity set out in search of materials,
03:01these stones probably seemed perfect to them
03:04for the construction of a structure as impressive as Stonehenge.
03:07In fact, we have used Sarsen stones in all kinds of works,
03:11from Roman villas to medieval churches,
03:13through road borders and cultural walls.
03:16We could say that these stones were the favorite material of the builders of Antiquity
03:21and that they continued to be popular even in the modern era.
03:24This led scientists to wonder if all the Sarsen stones
03:28used to build Stonehenge did not come from the same place.
03:32They identified sites throughout the United Kingdom,
03:35in regions such as Oxfordshire and Kent.
03:38After hundreds of years of study,
03:40geologists finally have the appropriate type of technology
03:43to determine the origin of the stones.
03:46I would like to tell you that this is a secret place,
03:49very far from the site.
03:51But it turned out that the Sarsen stones actually come from Westwoods,
03:55a forest located very close to Stonehenge.
03:58A new factor came into play when excavations revealed stone holes,
04:02indicating that at least 6 pillars of blue stone
04:05had been removed from the hills of Preselie on the site of Woundmen during prehistory.
04:10There was a stone circle there,
04:12and we think that some of Stonehenge's rocks
04:15were recovered in this older circle.
04:17If this is true, it could be that Stonehenge
04:20is part of a much larger set of ancient sites.
04:23If this is the case, Stonehenge would only be the cherry on top
04:27of a larger project.
04:29A bit like the masterpiece of a landscape of monuments,
04:32mounds, stone circles and other very impressive things.
04:37This is why scientists absolutely want to know where the stones come from.
04:42This could allow us to understand why and how Stonehenge was built.
04:47Stonehenge did not appear overnight.
04:50It was built in several stages over hundreds of years.
04:53It was probably not the work of one person,
04:56but of a large community project that evolved over time.
05:00Each generation of builders brought their own ideas,
05:03creating a structure that would last for centuries.
05:06The first step dates back to about 3,100 BC.
05:10A circular ditch was dug,
05:12and some blue stones were installed,
05:14forming a kind of starting ring.
05:17Later, they added the stones of Sarsen
05:19and even overhauled some of them with horizontal stones
05:23in order to form these famous arches that you see today,
05:27what are called the trillites.
05:29These builders of antiquity had many challenges to face.
05:32How did they move the stones?
05:34An old theory, known as the road of ice,
05:38suggests that the stones were moved on natural paths
05:41and glazed over several winters.
05:44They would have simply made the stones slide to Stonehenge.
05:48But we are talking about a distance of more than 160 km,
05:52so it's pretty unlikely.
05:54Anyway, this theory was denied
05:57because it was warmer at the time than it is today.
06:00There is also the theory of the river.
06:03The stones would have been transported by waterway
06:06from their extraction site to the site.
06:09But the stones of Sarsen are far too heavy for that.
06:12This theory has therefore also been abandoned.
06:15Clearly, no one knows how the stones were moved.
06:19Research conducted at Stonehenge
06:21revealed another interesting scientific element.
06:24A recent laser examination of the stones
06:26revealed the different methods of work used
06:29and showed that some parts of the monument
06:31were more carefully worked than others.
06:34In particular, the northeast side
06:36and the internal faces of the central trillites
06:38were meticulously carved.
06:40For your information, a trillite is a structure made up of three stones.
06:44Two huge monoliths are surmounted by a third that connects them.
06:48In Greek, this word simply means
06:50who has three stones.
06:52Anyway, the big question
06:54and the reason why Stonehenge is so famous
06:57is to know why it was built in the first place.
07:00Theories go a long way
07:02and some seem straight out of a series of science fiction.
07:06Here is a brief overview of the most popular ideas.
07:09There is of course the theory of the solar calendar.
07:12It assumes that the stones are aligned on the movements of the sun,
07:15especially during solstices in summer and winter.
07:18During the summer solstice,
07:20the sun rises to the left of the Heel Stone,
07:23the only stone outside the main circle,
07:25thus illuminating the entire monument.
07:28Some say that this is a kind of ancient calendar
07:31allowing to mark the longest and shortest days of the year.
07:35Some archaeologists believe that Stonehenge
07:37could have been an ancient healing site.
07:40Pieces of blue stone bear traces of burin,
07:43probably made by people who believed
07:45that they could cure diseases.
07:47According to a theory,
07:49people came to Stonehenge from all over the country
07:51in the hope of finding a cure for their illness.
07:54Some think that Stonehenge was a very popular place,
07:57a place where people gathered.
08:00Some evidence suggests that communities
08:02very far from each other
08:04met in Stonehenge for celebrations,
08:07festivities and ceremonies.
08:09An examination of the bones found nearby
08:12shows that people sometimes traveled hundreds of kilometers
08:15to gather on this site.
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