Afghanistan: Salang Pass & Tunnel

This high elevation tunnel was built by the Soviet Union in 1964 and was an absolute engineering marvel at the time – 2.67 km (1.66 miles) long and cutting through Hindu Kush mountains at the elevation of 3,400 m (11,200 feet). It then reduced the travel time from Kabul to Mazar-i-Sharif to 8–12 hours from 72 hours via older routes. The tunnel is in a rough condition, although there’s been efforts by the Taliban to fix and upgrade it – the asphalt is gone and it’s mostly rough gravel now, poorly maintained, with inadequate ventilation, dust, smoke, no lighting, and severe potholes. It was originally designed for 1,000 vehicles daily, it now handles around 16,000, causing massive congestion of trucks, buses, minibuses, and lots of Toyota sedan in really beat up states – all trying to get there first. In 1982, a fire engulfed a Russian military convoy resulting in up to 2700 deaths (Russian and Afghan), in 2010 the tunnel was hit by an avalanche resulting in 175 dead, and in 2022 a fuel tanker exploded inside the tunnel killing 27.