Most people treat America's highways like a means to an end — just something to get through on the way to somewhere else. But if you've ever driven a long stretch of open road with nothing but sky ahead and miles behind you, you already know it can be so much more than that. The US has one of the most extensive road networks in the world, and some of its highways stretch so far they cross a dozen states and just about every kind of landscape the country has to offer.