The Pan-American Highway

The Pan-American Highway is a road that goes from Prudhoe Bay, Alaska, in the Arctic Circle, to Ushuaia, Argentina, known as the most southern city in the world. It was going to be a railroad, but then cars were invented and that made construction easier. The United States has the most miles of the highway, but we had to cheat a bit to actually claim that. But a hundred years after the project was initiated, the highway is still not complete. The real problem is the Darién Gap, in southern Panama and western Colombia. So the highway gap is right where the two American continents meet.  

Jay Foreman and Mark Cooper-Jones make jokes aplenty while explaining how the Pan-American highway was conceived and what stopped its completion. There's a sponsor message from 4:43 to 6:10, and everything after 11:06 is promotional. (via Damn Interesting)