The Passo San Boldo is a small mountain pass in the region of Veneto, Italy. The passage is in the southern Alps and connects Belluna Val > Mareno Val n a height of 706 m. The mountain pass is named SP 635 and has only one runway. The traffic is regulated by several sets of lights. There is a speed limit of 30 km/h and a maximum height of 3.2 meters. There are five tunnels dug into the rock with sharp turns and six bridges. The road was built in 1918 in just three months.