Another stop on my places to see list, though I am not sure I really want to travel on it, is the Yungas Highway in Bolivia. This 10 foot wide, one lane highway is rated as the most dangerous in the world. It traverses the side of the Andes on it's way to La Paz, Bolivia. It has a 3000 foot drop on one side and no guardrails, plus it is extrememly steep in places. All of these factors combine to give this highway a very high death toll, as cars and trucks routinely careen off the edge into the jungles below.
I would love to go and see this just for it's sheer scale and the danger it represents, but getting me to drive on it might be a hard proposition. This is man against nature at it's most basic a raw level.
By the way, it has become fashionable to mountain bike down this road, and a cottage industry that caters to foreign mountain bikers has sprung up. It is not in any means safe, as many of these same mountain bikers have plunged to their screaming death from the sheer face of the cliffs as they have overshot turns, or fallen down unseen holes hidden by jungle foliage.