Pan-American Highway

The Pan-American Highway is more of an idea than an actual road. It runs from Ushuaia in Tierra del Fuego, Argentina all the way to Prudhoe Bay, Alaska. This allows you to drive from the most extreme southerly tip of South America to the most extreme northern point of North America. We're talking nearly 30,000 miles of "road." For the purists out there, there is unfortunately one 54 mile stretch of rainforest in Panama that is impassable; you must take a ferry. Or get very, VERY creative.

With the exception of overlanding the world (more on that later), this is probably the most extreme road trip you can take. Period. To be done properly, I think this should be done on a motorcycle.