The climb from Posada de Valdeón to the Puerto de Pandetrave can be divided into two parts. The separation of the parts is in Santa Marina de Valdeón, a village reached after 4 kilometers of cycling. The first part begins with a kilometer warm-up (5%) but the 3 kilometers after that are quite a challenge. This is where the steepest kilometer of the ride is (11.4%). In addition, within these 3 kilometers the gradient varies enormously, more than can be shown in the profile with its 500 meter segments. There are even descending sections while the steepest 250 meters have a slope of 14%. After Santa Maria the climb becomes easier and more steady. Almost all 500 meter segments now have a gradient of 6 or 7%. Compared to the first half, the road surface is worse in the second half of the climb and the road narrower. The latter always enhances the experience of nature, at least for me. In addition, one can here enjoy the lush green scenery and some impressive massifs of the Picos de Europa. There is little traffic on the road.