One of my favourite places is the Externsteine (
www.externstein.de).
there is very beautiful forest with special characterful trees beside the stones themselves.
On the picture you can see some entries to a cave that is dug insede the sandstone, today it is normaly closed, but the last months you could sneak inside, for me special because for long time we could not get inside.
though sitting outside the cave and making music, specially singing, is already very special inside there is a very special accoustic.
The echo or reverb is not so long but the resonance of some tones very very strong, some of the tones i found i am going to mention next days..
i believe that this room was made to recitate runes as in india it is done with the sanskrit.. runes are not spoken, the german verb ist raunen for the way of "speaking" them( a very deep and silent way of speaking, with a lot of resonance in the voice)
..and if you "raun" the runes you resonate with the whole room strongly..
..to be continued..