There's a reason the mixtape (or CD, or playlist, or .zip file) holds such sentimental power. A good mix can feel like a letter from a best friend, with each track carefully aligned with one's personal tastes. But the truly excellent ones are like being handed a key ring to the cosmos, with each track unlocking a door to a new world to explore. North Carolina may not take up that much space on a map, but it's home to an abundance of musical worlds. North Carolina Public Radio has spent the past year talking to artists about their favorite songs that say something about our home state.