Located just outside the Arctic circle in eastern Siberia, the Mirny- Udachny road is a real adventure. The drive is strictly off limits to outsiders without a special permit and the authorities regard any foreigners with considerable suspicion.
Located in the Sakha Republic of Russia, the road is 515 km but expect more than 20 hours driving. It links Mirny, the diamond “capital” of Russia, on the Irelyakh River and Udachny, a small town currently mined to a depth of more than 630m, which makes it one of the 10 deepest open-pit mines in the world.
The road is gravel and permafrost, a thick subsurface layer of soil that remains below freezing point throughout the year. This trail passes through remote areas, so you need to be prepared. Expect extremely harsh climate conditions and frozen surface of the road. This road tests the skill, and courage, of any driver.
Pic&more info: http://www.sibirskyextreme.com/page/16/