The Verdon Gorge is a canyon up to 700 metres deep in the limestone of Provence, in southern France, with a green river running twenty-five kilometres along the bottom, and these walls are where sport climbing was invented. François Guillot opened the first of the great long routes here, La Demande, in 1968. Through the decade that followed the limestone was bolted from the top down. By the mid-1980s the Verdon was the first major cliff in the world climbed almost entirely on bolts placed in advance, a style that went from here to crags everywhere. The river's colour is glacial rock flour carried down from the Alps. It runs out at the western end into Lake Sainte-Croix, which looks like the oldest thing here and is the newest. The valley was dammed in the 1970s, and the village of Les Salles-sur-Verdon went under the water. Its people were moved to a new village built higher up the shore, where they now look out over their own drowned streets.
From the beaches at that end you can hire a canoe or kayak by the hour and paddle upstream into the mouth of the gorge. The rock drops sheer to the water there, and the channel pinches to a few metres across. The Route des Crêtes runs the southern rim in a one-way loop of belvederes, each one opening a new angle as the canyon drops hundreds of metres beneath your feet. Griffon vultures ride the updraughts at eye level there. They had been gone from the Verdon for most of a century, and the first twelve were released above Rougon in 1999. You reach the floor on the Sentier Martel, a fifteen-kilometre day past sculpted pools and sheer walls, down steel ladders and through a long unlit tunnel. The Pont de l'Artuby crosses a side gorge on a slender arch with 182 metres of air under it. And from almost any belvedere, if you look carefully at the pale rock opposite, there are climbers on it, hanging like specks halfway down.