Considering the Hotel Dreiflüssehof in Passau?
A VT member wrote the following comment about visiting Passau:
The wolrd's biggest Church Organ! by Roeffie
The Organ at Dom St. Stephan
What a mighty sound! Normally I don't like listening to church or classic music, but coming out of this organ with it's 17774 Pipes and 233 Registers it's marvelous to hear.