This is a challenging mountain stage with an even tougher finale. The roads are wide and straight up to San Daniele. Before entering Carnia, the route takes in climbs up Monte di Ragogna (with gradients steadily over 10% for the first 2.5 km, and ramps topping out at 16%) and Avaglio (with milder slopes). The route then takes the road to Paularo (with some tunnels along the way), leading to the foot of Passo Duron. The climb is short yet steep, with gradients peaking 18% at points. The route drops down into Sutrio and takes in the Sella Valcalda climb, and then reaches the foot of the closing climb in Ovaro. Monte Zoncolan is regarded as the hardest climb in Europe: 10 km at an average 12% gradient, with peaks topping out at 22%. There are three short tunnels along the route in the last kilometre. Final kilometres: the final kilometres rise steeply. With 3 km to the finish, two (left-right) hairpins alternate with an almost flat sector (the only one of this stage). The climb then features gradients from 12 to 18%, up to the three tunnels (150 m – 60 m – 110 m) leading to the final 500 m, with an average 11% gradient, and peaks reaching as high as 16% by the hairpin located 250 m before the finish. The road surface is tarmacked and the roadway is 5 m wide.