This 1905 stamp shows Kaiser Wilhelm II giving a speech in 1896 for the German Empire’s 25th anniversary. Because of their high face value, the stamps were printed only in sheets of 20. The scarcity of inverted images like this one suggests the error occurred in only one sheet.
unused copy of 5m Kaiser Wilhelm II stamp with inverted center; error
Museum ID: 0.3199188.8.131.52