Hit something with a hammer, and it makes a sound. If you’re lucky, it might even make a pleasant sound, which is the idea behind the Great Stalacpipe Organ in Luray Caverns, Virginia.

All that warmth, enthusiasm and ambition still resonates through every pipe ... for your collection of strange instruments from around the world - the Heldenorgel in the fortress of Kufstein ...

"He improved on the concept in every conceivable way," Stewart ... So far, he has made 11 of the instruments for people around the world, from Africa and the United States to the Stratford ...