The 10 villages of the Onsernone Valley, in the southernmost Swiss canton of Ticino, are linked by a single road that seems only marginally wider than your outstretched arms. Supposedly there are 300 bends between Auressio, at the bottom of the valley, near Locarno, and Spruga, at the top, where the road runs out just short of the Italian border. In Spruga there’s a small car park and turning area. It occurred to me when I got there that this car park was the largest piece of flat land I’d seen since leaving Locarno. From this point you can continue on foot into the forest — across the Isorno river, into Italy — but cars can only turn around.

I’d been told there was a witch in Spruga and vaguely hoped I might meet her. But I met nobody. I saw nobody. Not a black cat stirred. The windows of the Bar Onsernonese, where I might have made inquiries, were shuttered, the door locked. The wind soughed gently in the trees and that was all; the village seemed to have something of the Wild West about it.

The Onsernone Valley is sometimes described as the wildest valley in Switzerland. Because of its east-west orientation, each side has its own microclimate and flora. The shadowy north-facing slopes are dense with beech, silver fir and larch. Portions of the bright, south-facing slopes, where the 10 villages cling on for dear life, were long ago terraced and planted with chestnut orchards and rye. But over the past hundred years or so, in which time farming was all but abandoned, these spaces have become a study in afforestation. They have rewilded themselves. Whether it’s actually the wildest valley in Switzerland or not, it’s almost certainly wilder today than at any time since humans settled here in the late Middle Ages.