During last month, Dudendance have been performing Borderlands, their hauntingly lovely promenade-installation work, in three ruined abbeys in the Scottish Borders - Kelso, Jedburgh and Dryburgh, where the Andante Chamber Choir sang live but eerily unseen.
What we did see were apparitions. A dozen or so female figures, all in white. Full skirts billowing, faces shadowed by period bonnets, they silently materialised among the crumbling stones as if they had in fact drifted out from between the cracks in the walls. There was no attempt, in the costuming, to tie these spectral forms to a specific period. Instead, as the slow-moving forms melted into the masonry, or stretched out on gravestones or on grass, it felt as if holographic flashes of distilled history were being projected across time.
It was as if echoes of Dryburgh's monastic past - and of the fires and wars that ravaged it - were set in stone. On a sunny Sunday afternoon, the grass still wet from an earlier shower, those stones were reminding us of when the Abbey wasn't a tourist attraction or framed, like a romantic folly, in a landscaped estate.
When a bell tolled, and the choir - cunningly out of sight in the 13th century chapter house - sang an exquisite Ave Maria, all the meaningful shades of Borderlands that Clea Wallis (director) and Paul Rous (choreographer) had threaded through this project came together in a profound and poetic moment. The Abbey's soul, if you like, whispered and sang to us across time.
This is where Borderlands catches the imagination, not just in terms of a specific site but in our daily life. The show challenges its audience to think outside the box of our own present-day existence in a place and connect, if only in passing, with lives lived previously in that place. If history has a DNA, then it is in the people: the dates we memorise for exams are just the markers and milestones along the way.
Other than the singing, and an intermittent soundscape, the whole event moved on in tranquil silence - even small children and boisterous dogs hushed and stilled, as a darkened archway suddenly framed a pale shape or long trails of ectoplasmic drapery spooled down from an upper window.
Cameras clicked, but no-one spoke as more and more visitors stopped to stare, and then stayed.
At one point, three of the shrouded, barefoot cast came into view bearing huge white standards which they unfurled and waved - the sound of the rippling cloth whipping through the air like a wan rallying cry to warring armies long gone. The battles over our borders are no longer fought on these grounds, but in ballot boxes.
On paper, what Dudendance have achieved looks simple, but the minimalism of this performance is its strength. Each moment of intervention has been carefully plotted, placed, rehearsed.
Afterwards, it feels like an illusion - one that we'd conjured up for ourselves on a visit to Dryburgh Abbey.
As for the ruins, they now have more memories lodged in their sandstone.