Col de la Pierre Saint-Martin from Isaba via Larra Belagua

The NA-137 rises 25.4km through wooded valleys and open mountainside, gaining 977m to 1,763m. The average gradient of 3.8% disguises ramps of 8.9% — the kind of gradient that turns plans into prayers. 11 hairpins punctuate the ascent, offering brief respite in the corners before the gradient bites again. The road reaches 1,763m — high enough to feel the altitude on tired legs. Located in Navarre, Spain.