The doctrine not only called for a "back to the land" approach and re-adoption of "rural values"; it held that German land was bound, perhaps mystically, to German blood. Peasants were the Nazi cultural heroes, who held charge of German racial stock and German history—as when a memorial of a medieval peasant uprising was the occasion for a speech by Darré praising them as a force and purifier of German history. Agrarianism was asserted as the only way to truly understand the "natural order." Urban culture was decried as a weakness, labelled "asphalt culture" and partially coded as resulting from Jewish influence, and was depicted as a weakness that only the Führer's will could eliminate.