By David Sillito
BBC News Arts correspondent
Each light and stone was airlifted to agreed locations
Hundreds of walkers in the Isle of Skye have been gathering for the official opening of a startling new nocturnal art project.
The three-kilometre route to the remote nature reserve surrounding the Old Man of Storr is being lit up to create a strenuous mixture of music, climbing and environmental art.
More than 10,000 people are expected to turn out over the coming weeks to make the climb into glowing cloud formations.
The project has been created by the environmental artist Angus Farquhar and has cost more than a million pounds to set up. More than 50 guides and technicians are involved in helping people up the dark and treacherous path.
It begins in a forest echoing with the sound of bronze age horns. That is then followed by a long climb, in the dark, to a cold, damp corrie high in the hills.
By midnight the walkers are on the top of a rocky outcrop listening to German poetry and staring at misty glowing stones.
On a good night you can see what looks like the surface of the moon, on a more typical evening the cloud has come down and the lights appear to roll in and out of vision, occasionally revealing fragments of the landscape.
On a bad night you are lucky if you can see the person next to you.
On the way down Gaelic folk songs are sung from the top of a distant hill which mix in with some gurgling music that sounds like rumblings from Earth's inner core.
On the long careful journey down the new path the walkers are accompanied by shining vapour ghosts who appear to be walking through the woods.
It takes two hours and was for some a rather taxing form of art.
But for Angus Farquhar it is the culmination of four years work.
Funding from the Scottish Arts Council, The National Endowment for Science, Technology, and the Arts (Nesta) and a large number of other groups - including a company that has helped kill off the local midge population - has made this month-long experiment possible.
Shining vapour ghosts appear to be walking through the woods
The big problem has been finding a way of installing machinery into the fragile habitat.
Many of the local plants are rare, protected and easily damaged. Each light and stone has therefore had to be airlifted by helicopter to agreed locations. The group was not allowed to have generators on the route and so hydro-electric power is used to charge up the batteries that power the lights.
Local ecologist Chris Tyler says the plan initially caused "panic" but after "four years' hard work it seems they have got it about right".
The end effect is subdued rather than dramatic.
But the first groups of walkers who made it to the top were impressed. For some the exhilaration was a mix of awe at the visual and musical spectacle and relief that they had made it down the hill without serious injury.
Angus Farquhar's next project will take place within the Arctic Circle, but he says he hopes the Storr Project will be a model for future night-time eco-friendly art installations across the Highlands.