Have you ever heard of a seven string guitar?

I don’t like to think I’m “out of touch” but when Carl told me that he needed to buy some new strings for his 7 string guitars I thought he was joking! I laughed at thim and told him that this wasn’t April Fool’s Day! I felt rather foolish when he showed me one of his seven string guitars! I wonder if there are any popular bands that I’ve listened to where some of the musicians play a seven string guitar!