I'm betting none of us have ever heard the name Mary McCoy. But she's not only a well-known name near Houston, Texas, but she's also officially in the Guinness Book of World Records. She's the longest serving female DJ in history, and at 85, she's still on the air, having been in radio since 1951 - at the tender age of 12. 

All told, she's been working in the business for an incredible 72 years.

If that's not enough, consider this - she did it all at the same station, despite years of call letter and ownership changes. And as the linked article notes, she even once shared the stage with a then little-known Elvis Presley. 

Texas woman becomes longest-serving female radio DJ in the world