Collá las Agujas is one of the highest unpaved roads of Spain

Collá las Agujas is a high mountain peak at an elevation of 2.101m (6,893ft) above the sea level, located in the province of León, Castile and León, Spain. It’s one of the highest roads of the country.

The road to the summit, located within the Redes Natural Park, is gravel, rocky, tippy and bumpy at times. Expect a trail pretty steep (with sections up to 15%) and plenty of hairpin turns. Wet conditions may make for tough driving along the muddy road. Located within the San Isidro ski resort, it’s a chairlift access trail. The road is impassable in winters. Great trail for experienced wheelers. Avoid driving in this area if unpaved mountain roads aren't your strong point. 4x4 required. Stay away if you're scared of heights.
Pic: http://www.diariodeleon.es/noticias/leon/diputacion-disenara-plan-rentabilizar-san-isidro-todo-ano_912291.html