The Carolina-Duke rivalry is a competition between two universities, the University of North Carolina at Chapel Hill (Carolina) and Duke University (Duke). Lots of people care a lot about which one is better! It's kind of like a big game of hide-and-seek, but instead of just two teams, there are whole groups of people who want their school to win.
Carolina and Duke are colleges that are really close to each other, so they play a lot of sports against each other. That makes the rivalry even more fun! People talk about these games for days before and after they happen, and they get very excited about watching them.
People who go to each school often wear colors or clothes that show they support their team, like t-shirts or hats. Sometimes, they even paint their faces or their bodies in their school's colors! They cheer a lot during the game and try to make louder noise than the other team's fans.
The rivalry isn't just about sports, though. People who go to one school might feel like their school is smarter or cooler or more fun than the other school. This makes them want to prove that their school is better in everything they do!
The rivalry has been going on for a long time, so people who grew up rooting for one team might raise their own kids to love that team too. That's why the Carolina-Duke rivalry is still going strong after all these years!