#1 Karakoram Highway
This highway linking Pakistan and China reaches altitues of 16,000 feet and is no laughing matter. You wouldn't want to fall off this one.
#2 Guoliang Tunnel Road (China)
This tunnel/road is 1,200 meters long and was built by locals in the 70's. It took 5 years to construct this road that tunnels in and out of some of the steepest peaks in China.
#3 The Road Through The Himalayas
#4 Road Of Death
This Bolivian road is not only long, but it is called the road of death for a reason. It is responsible for 100-200 fatalities a year.