Passo San Boldo is a mountain pass located between the cities of Trichiana and Tovena (Cison di Valmarino) in Veneto, Italy, at an elevation of 706 m (2,316 ft) that lies in the northern reaches of the Italian Alps. The most challenging part of the climb is a short stretch of 700m including 7 hairpin turns. It’s one of the famous hairpinned roads in the world.
The road still remains an adrenaline-pumping journey and is definitely not for the faint of lungs, heart, or legs. The 17km route goes from Trichiana (in the Belluna Valley), at an altitude of 329m, to Tóvena (in the Val Moreno), at an altitude of 272m, through an altitude of 706 m. The drive is definitely worth it.
The road, called SP 635, just allows traffic in one direction, alternating with traffic lights. The ramp to access the south side by the neck back is a nearly vertical wall with a series of five turns through tunnels carved into the rock connected by six bridges. This road replaced a steep path leading up to summit that existed since the nineteenth century but only during the First World War that project succeeded. Between February and June 1918, the Austro-Hungarian army managed to build the road in less than three months. After this fact, the road got the nickname of "road of 100 days."
This road is usually open all year, but it can be closed anytime when the access is not cleared of snow. 1400 people, including prisoners of war and women, children and the elderly in the area, worked day and night to complete the strategic route for refueling during the Battle of Piave. Despite the topographical conditions, the slope could not exceed 12% for the passage of heavy vehicles and artillery.
The road is stunning. It’s asphalted and includes 18 numbered hairpin turns, 6 of them hidding inside tunnels. It was built by 7.000 workers (mostly Russian prisoners and women) and was completed in a record time, hence it was inaugurated in June 1918 with the nickname "the road of 100 days".
The works began in 1914 under the direction of engineer Giuseppe Carpenè, which employed 500 migrants repatriated between 1914 and 1916. During World War strategic reasons motivated the Austrian engineers (under the direction of Nikolaus Waldmann) to complete the work in a short time, being its construction planned for January 1918, with five additional galleries that now characterize the climb.
Despite the fact that the road is located in Italy, the road is named after a Spanish hermit, called Boldo. He was a hermit living in these mountains and some years late he would become saint, San Boldo.