It’s this fear of disappointment that has stopped me visiting sooner. Like a two-bit floozy, Stonehenge’s reputation precedes it. I’ve heard some bad things: that it’s surrounded by a horrible wire fence and that it’s in the middle of a snarl of busy motorways, which ruin the magic of the place.

“That’s just American websites written by people who don’t know what they’re talking about,” scolds Pat Shelley, who runs guided tours of Stonehenge and nearby Salisbury. He tells me I’ll be impressed.

And he’s right. Framed by the windswept, grassy plains of Wiltshire, Stonehenge is as magnificent and iconic as you could hope it to be.

Most visitors have to make do with viewing the stones from behind a roped-off area (or from behind the perimeter fence if they’re too tight to pay the entrance fee) about 15m away from the stones. It’s not a bad viewpoint, but we lucky few are among 5000 people allowed to walk among the stones this year.

I’m instantly struck by how atmospheric it is here. Thankfully the traffic noise from the nearby road is barely audible and, given that our visit happens after official closing time, we have the place to all ourselves (well, all except for the guards who keep the stones under 24-hour survellience).

As we wander among the huge  sarsen stones, dragged here from north Wiltshire thousands of years ago, the wind howls through them adding to the timeless eeriness of the place.

Some stones have tumbled over and others have disappeared completely. What I’m not prepared for is the stones’ surfaces, which are encrusted with miniature plant life: “74 kinds of lichen,” Shelley informs us, with new growth constantly replacing old.

He also points out the impressive craftmanship. The lintels that lie across the top of two standing stones, creating a giant doorway, don’t just balance there, Shelley tells us — they are morticed and jointed. Each weighs around 25 tonnes.

“I wouldn’t want to be under one of them when it was going down,” he jokes.

Thanks to the combined efforts of various archeologists over the years, we know quite a lot about Stonehenge. We know it was erected roughly 5000 years ago and started out as a circle of upright timber posts. The

smaller bluestones, which make up the inner ring, came all the way from west Wales (though no one’s sure exactly how) at around 2500 BC, and the sarsens after that. For its time it was a huge engineering feat, requiring the labour and commitment of hundreds of people.

We also know that the Druids (or ‘interlopers’ as Shelley calls them) definitely didn’t build it, contrary to a 17th-century theory. Though that doesn’t stop the white-robed weirdies from flocking here each year for the summer solstice.

But the one thing we still really don’t know about Stonehenge is this: what the hell was it for?

“It’s use was ceremonial,” says Shelley, “which is short for ‘we haven’t got a clue!’”

Lots of ancient burial sites have been found near to Stonehenge, but whether this means the monument was a cemetery or something else is still up for debate.

This year the first major dig in a decade was undertaken at Stonehenge by leading British archeologists, professors Timothy Darvill and Geoff Wainwright, who are hoping to scotch the burial place theory and prove Stonehenge was a place of healing instead (see breakout).

Come autumn, we will probably know the results of the dig. As I look at the ancient monument in the dying light, part of me hopes they don’t find anything conclusive. I like the mystery that surrounds Stonehenge. It’s part of its eternal charm.

» Alison Grinter travelled to Stonehenge with Anderson Tours (020-7436 9304; Special access/private viewing tours from £75.

Stonehenge: The theories


A graveyard

Stonehenge acts as giant tombstones to the dead, possibly a ruling dynasty, argues Mike Parker Pearson from Sheffield University. He came to his conclusion after conducting tests on human remains taken from the site in the 1950s.

The Lourdes of the Bronze Age

No it wasn’t, counter archeologists Geoff Wainwright and Timothy Darvill. It was like Lourdes in France, where the sick would seek cures from the bluestones, believed to have healing powers. This, they argue, is why the nearby graves are filled with bodies of the sick and deformed.

A sundial

Another theory suggests Stonehenge was built as a temple to the sun and the changing seasons, with its stones aligned to mark midsummer and midwinter.

A giant computer

This theory gained currency in the ’60s, at the dawn of the computer era. Scientists thought it was a giant calculating machine. Really, they should have stayed off the acid.

A fertility symbol

Seen from above Stonehenge looks like female sex organs, says British Columbian gynaecologist Anthony Perks. But as one archeologist pointed out, people didn’t have hot-air balloons in those days so how would they have known?