Zagori

In northern Greece, an hour from Ioannina, sit some forty villages built from the same grey stone as the mountains around them — not a concrete house among them, because the whole area is protected. Eighteenth-century arched bridges link them, and between them opens a gorge a kilometre deep.

The Vikos gorge holds a Guinness record as the deepest in the world relative to its own width — about a thousand metres deep and, at its narrowest, only a few hundred metres across. The hike from Monodendri to Vikos village is twelve kilometres and five to six hours one way, with roughly nine hundred metres of descent and a four-hundred-and-fifty-metre climb at the very end.

What to know in advance: it's a one-way trail with no public transport at either end — a taxi back needs arranging ahead. If you're not hiking, there are viewpoints you can drive to, and the Voidomatis — one of the cleanest rivers in Europe — with natural pools to swim in.