From Wikipedia:
A menhir (from Brittonic languages: maen or men, "stone" and hir or hîr, "long"), standing stone, orthostat, or lith is a large man-made upright stone, typically dating from the European middle Bronze Age. They can be found solely as monoliths, or as part of a group of similar stones. Menhirs' size can vary considerably, but they are generally uneven and squared, often tapering towards the top.
They are widely distributed across Europe, Africa and Asia, but most numerous in Western Europe; particularly in Ireland, Great Britain, Brittany and France, where there are 1,200 menhirs in northwest France alone. They were constructed during many different periods across pre-history as part of the larger megalithic cultures in Europe and near areas.
Some menhirs have been erected next to buildings that often have an early or current religious significance. One example is the South Zeal Menhir in Devon, which formed the basis for a 12th-century monastery built by lay monks. The monastery later became the Oxenham Arms hotel, at South Zeal, and the standing stone remains in place in the ancient snug bar at the hotel.
Where menhirs appear in groups, often in a circular, oval, henge or horseshoe formation, they are sometimes called megalithic monuments. These are sites of ancient religious ceremonies, sometimes containing burial chambers. The exact function of menhirs has provoked more debate than practically any other issue in European pre-history. Over the centuries, they have variously been thought to have been used by Druids for human sacrifice, used as territorial markers, or elements of a complex ideological system, or functioned as early calendars. Until the nineteenth century, antiquarians did not have substantial knowledge of prehistory, and their only reference points were provided by classical literature. The developments of radiocarbon dating and dendrochronology have significantly advanced scientific knowledge in this area.
The word menhir was adopted from French by 19th-century archaeologists. The introduction of the word into general archaeological usage has been attributed to the 18th-century French military officer Théophile Corret de la Tour d'Auvergne. It is a combination of two words of the Breton language: maen and hir. In modern Welsh, they are described as maen hir, or "long stone".
Almost nothing is known of the social organization or religious beliefs of the people who erected the menhirs. There is not even any trace of these people's language; however we do know that they buried their dead and had the skills to grow cereal, farm and make pottery, stone tools and jewelry. Identifying their uses remains speculative. Until recently, menhirs were associated with the Beaker people, who inhabited Europe during the European late Neolithic and early Bronze Age—later third millennium BC, c. 2800–1800 BC. However, recent research into the age of megaliths in Brittany strongly suggests a far older origin, perhaps back to six to seven thousand years ago.
Many menhirs are engraved with megalithic art. This often turned them into anthropomorphic stelae, although images of objects such as stone axes, ploughs, shepherd crooks and yokes were common. With the exception of the stone axe, none of these motifs are definite, and the name used to describe them is largely for convenience. Some menhirs were broken up and incorporated into later passage graves, where they had new megalithic art carved with little regard for the previous pictures. It is not known if this re-use was deliberate or if the passage grave builders just saw menhirs as a convenient source of stone (Le Roux 1992).
During the Middle Ages, standing stones were believed to have been built by the giants who lived before the biblical flood. Many of the megaliths were destroyed or defaced by early Christians; it is estimated that some 50,000 megaliths once stood in Northern Europe, where almost 10,000 now remain.
In France, Brittany stands out in the distribution of menhirs by virtue of both the density of monuments and the diversity of types. The largest surviving menhir in the world is located in Locmariaquer, Brittany, and is known as the Grand Menhir Brisé (Great Broken Menhir). Once nearly 20 meters high, today, it lies fractured into four pieces, but would have weighed near 330 tons when intact.
Alignments of menhirs are common, the most famous being the Carnac stones in Brittany, where more than 3000 individual menhirs are arranged in four groups, and arrayed in rows stretching across four kilometres. Each set is organised with the tallest stones at the western end, and shorter ones at the eastern end. Some end with a semicircular cromlech, but many have since fallen or been destroyed.
The second largest concentration of menhirs in France is at the Cham des Bondons, located on high open limestone plain in the granitic Cévennes. The site is today protected by the Parc National des Cévennes. From the time pastoralism was established, the site was kept open by controlled burning and grazing.
From the Si Belle Villa site:
A Menhir is a tall, vertically placed standing stone, whilst a Dolmen is a table-like structure comprising a large slab laid horizontally on two smaller stone supports (orthostats). When there are a number of dolmens side by side, it is described in French as a covered passageway. The entrance is usually protected by a Menhir positioned within a few metres and which has ‘magical’ qualities.
What was the purpose of menhirs? Firstly, they come in different shapes: convex, triangular, trapezoid or oval. Convex menhirs mark the entrance to a dolmen, carefully positioned to allow the rays of the rising sun to light the end of the chamber once a year, on either a solstice or an equinox. Thus they are astronomical monuments. It seems that triangular menhirs indicate routes, a map, directions… whilst ovals designate a border, a watershed, or indeed a memorial to a notable event in that place in the past.
