The Great Stalacpipe Organ

Have you ever been in a cave, admiring the stalactites, and thought they resembled a pipe organ? You're not the only one. In fact, Luray Caverns in Virginia has an instrument that can play those stalactites like an organ! The Great Stalacpipe Organ is an electronic device that taps into the stalactites with rubber mallets to produce musical notes. This lithophone is the largest musical instrument in the world. The device brings the notes together, but it doesn't change the actual note- those comes from the striking of the stones themselves. They were cataloged and tuned more than 60 years ago, but considering the way stalactites are formed, they made have to be re-tuned in a few thousands years.  

Veritasium takes us on a tour of the history of Luray Caverns and the musical instrument it contains. There's a one-minute ad at 4:38. (via The Awesomer)