Stage 17: Villadiego to Los Machucos. Monumento Vaca Pasiega, 180.5km
Amid Cantabria's mountain riches, the Vuelta has found an unused gem for a key summit finish. The cat-1 Collado de Espina is 9km long, derided by some as a goat track climb. Its first kilometre averages 13.3 per cent. There's a second steep section in the middle with ramps up to 18 per cent. It reaches a plateau for a kilometre of flat to the line.