Ulan-Daban Pass, a 4x4 border road

Ulan-Daban is an international high mountain pass at an elevation of 2.697m (8,848ft) above the sea level, located on the border of Russia and Mongolia.

Ulan-Daban Pass

Nestled in the Altai Mountains, in the Ukok Plateau, the road to the summit is not for the sissies. It’s totally unpaved and rocky. 4x4 vehicle required. The road has some narrow parts, impassable for 2 medium cars. Not recommended if you don't know how to reverse. 

Adverse weather conditions are common. The pass is 191 km (118 miles) long. It links Belyashi (in the Kosh-Agachsky District, the Altai Republic, Russia) with Хөх (Bayan-Ölgii Province in western Mongolia).
Pic: Владимир Шатунов