National Public Lands Day is the third Saturday in September. It's the largest single-day volunteer effort in the country for public lands, such as national parks. In celebration, Mammoth Cave will be offering a very special treat. 

The park will offer the Discovery Cave tour next Saturday for free. Guests will embark on this self-guided tour and they will be able to explore one of the cave's largest rooms, the Rotunda and explore the history and geologic origins of the Mammoth Cave system.

Registration is not required but guests are being asked to pick up their tickets at the visitor center. The tour will start at the Historic Entrance of the cave and will run for five hours from 10:00 a.m. until 3:00 p.m. CT.

Learn more about National Public Lands Day HERE.