Well kiddo, Cornwall is a place where a lot of people live and some of them believe in something called Christianity. Christianity is a religion where people believe in a special man named Jesus who they think is like a hero because he did good things to help people a long time ago.
In Cornwall, there are a lot of churches where people who believe in Jesus can go to pray and sing songs. These churches are usually big and have stained glass windows with pictures of Jesus and other important people from the Bible, which is a book that tells stories about Jesus and his friends.
People who believe in Christianity in Cornwall also celebrate special holidays like Christmas and Easter. Christmas is when they remember the story of Jesus being born and Easter is when they remember the story of Jesus coming back to life after he had died.
Some people in Cornwall might not believe in Christianity though, and that's okay too because everyone has their own beliefs and that's what makes us all special.