Route des Grandes Alpes

The Route des Grandes Alpes is a signed touring route of about 720 km from Thonon-les-Bains on Lake Geneva to the Mediterranean at Nice, crossing more than a dozen cols on the way. It includes the Col de l'Iseran, at 2,764 m the highest paved pass in the Alps, along with the Galibier, the Izoard and the Cayolle.

The drive

Three or four days is the right pace. A typical split is Thonon to Val d'Isère over the Colombière, Aravis and Cormet de Roselend; then Val d'Isère to Briançon over the Iseran, Télégraphe and Galibier; then Briançon to Barcelonnette via the Izoard and Vars; and a final day over the Cayolle or the Bonette to the coast.

The variety is what makes it. The Roselend is open and pastoral, the Iseran is bleak and high, the Izoard's southern side crosses the bare scree of the Casse Déserte, and the last descents arrive in olive groves.

In your Porsche

This is a tour a 911 was made for: enough luggage space for two people for a week if you use the rear seats, and a fuel tank that gives a comfortable range between mountain villages. A Cayman or Boxster has two boots and manages nearly as well. Mountain stations often have only unmanned card-operated pumps, so fill up when you can. Naturally aspirated cars feel the thin air above 2,000 m; turbocharged ones much less so. Some link roads are rough and narrow, which is where a low front splitter needs watching. A Taycan can do the route, but plan charging around the valley towns, since chargers are scarce on the cols themselves; the long descents put useful energy back into the battery.