In case anyone was interested the ballroom that Tatara and Chinatsu waltzed through is a like-for-like rendition of the great gallery at Schonbrunn Palace in Vienna - summer home of the Hapsburgs. Quite an interesting the place to visit (in the ostentatious, ludicrously expensive, multi-continental throne-room sort of way). https://en.wikipedia.org/wiki/Sch%C3%B6nbrunn_Palace