An old highway that goes up the California Pacific coast from LA to San Francisco. It rides the cliffs the whole way, with amazing ocean vistas. Curvy and thrilling--okay, a bit white-knuckles for some of the way. Some of the curves give you almost no shoulder with nothing but a cliff down and a sheer wall up. So there's not much room for error. Plus, you're probably concentrating on driving so much your first few times that you don't actually get to enjoy the scenery. Therefore, if you're only going to do it once, pull over periodically and enjoy the crashing waves.

Most people don't take 1 to travel from point A to point B, because it takes a lot longer. Sometimes that's not the most important thing, though.