Question: When did the former wife of Graf von Bismarck-Schönhausen donate a piece to the Smithsonian she purchased on her honeymoon with a different man?
Sentence (from "Alexander Schenk Graf von Stauffenberg"): His older twin brother Berthold Schenk Graf von Stauffenberg and youngest brother Claus Schenk Graf von Stauffenberg were among the leaders of the 20 July Plot against Hitler in 1944.
Relevant evidence: No