Morbihan has an abundance of megaliths.
They range from simple menhirs (the sort of thing Obélix carts around in the Astérix cartoons) to extensive burial complexes.

A menhir is a ‘long stone’ or standing stone. A dolmen is a ‘stone table’, supported at various points, which served as a burial chamber in times before written history. A cromlec’h is a stone circle. All these words of Breton origin are now the universally used terms for these structures in both English and French.

When driving along a country road, you frequently see signs to an allée couverte – a less elaborate form of dolmen. Typically, the covering stones as well as the support stones are roughhewn.

If they’re not too overgrown with nettles, and you’re reasonably supple, you can crawl inside or at least peer into the gloom from the open end.

Morbihan’s most celebrated standing stones are the stunning array at Carnac. Controversy still surrounds the now fallen Grand menhir of Locmariaquer. The most popular theory as to its purpose suggests that of a lunar observatory, linked to eight other sites, but sceptical scholars argue that three of these sites are non-existent, and that of the five remaining, one is in the wrong place. Further debate wonders whether the Locmariaquer menhir ever did stand or whether it fell (or was pushed) before the eight linked sites were constructed; and indeed whether the structures were in fact totally unconnected with celestial observation, being merely territorial markers.

The tract of land between Carnac and the Golfe du Morbihan possibly has the département’s densest population of prehistoric monuments, but there are plenty of others throughout Morbihan. Use the IGN (Institut géographique national) 1:25,000 scale walking maps and look for the red star indicators.

Excavations of graves of the people who built the stone structures have yielded little of substance. Pretty much all we know is that they were short, dark and hairy, and lived, if they were lucky, into their mid-30s. But their civilisation was long-lived – archeological evidence suggests that they were in the area for no less than 5,000 years.

They are thought to have built their dolmens in the following manner. First, an earthen bank was heaped up, its vertical side reinforced with stone; the massive construction stone was pushed up the slope, then tipped over into the vertical, the impact of its landing absorbed in sand or wood; then, finally, the roofing slabs were put in place and the earthen banks removed. Not quite the Millau viaduct – but impressive for the period!

The first thing that strikes you when you clap eyes on the megaliths of Carnac is the sheer scale of the site and the number of standing stones; that, and how orderly they all are. The second thing is how little is actually known about them.

Carnac is generally reckoned to be the most important prehistoric site in Europe, and it’s almost impossible to avoid comparisons with Stonehenge, even though Carnac has no horizontal lintel stones.

Among the few things that can be said about them with certainty is that they are not – as was feared briefly by US soldiers in 1944-45 – German antitank defences.

The stones have the rough-hewn appearance of flint, and are aligned in quasi-military ranks on a north-east by south-west axis. Scholars insist that the appearance of order that so impinges on the visitor at first sight is in fact deceptive. The site is to a large extent incomplete, because past generations have stolen stones to re-use for building and, more recently, farmers have removed more to save their crops from the trampling feet of academics and tourists.

It is widely agreed that the Carnac stones formed some sort of religious monument connected with their function as a rudimentary astronomical observatory. They are the largest of a whole system of outlying menhirs and standing stones, which lends weight to the theory of their astronomical purpose.

Further round the bay at Locmariaquer is the Grand menhir – now fallen – which can be taken as a point of alignment with eight other sites in the area, their axes corresponding to the rising and setting of the midwinter moon. One such axis forms a direct link, via Locmariaquer, between the tip of the Quiberon peninsula and the inland village of Trevas.

Before leaving, a trip to Archéoscope is highly recommended – an enclosed exhibition that explains most of what’s known about the site, with theatrical presentations of the latest theories on how the Carnac site must have originally looked.

If you enjoy exploring on your own, use the IGN maps to discover the plethora of individual menhirs that are way off in the woods and a lot further, in atmosphere, from the well-trodden paths of the tourist attractions. Some have names, such as Le Géant du Manio, north-east of the main site.