Bach + wood + forest = beauty!

I thought this was heavenly, then my kids watched it and were transfixed....
This young crew go to the woods of Kyushu, Japan. Engineer a massive xylophone (or is it a marimba?) to run down the slope of a forested hill. Take a wooden ball, place it at the top of said instrument, and push it. What do you get? Bach's treatment of a traditional church hymn! Namely, "Jesu, Joy of Man's Desiring."

There is also a film of how the xylophone was made, which is just as beautiful (you will practically cheer along with them!):