How can a colossal lie persist for decades without arousing any suspicion? The true but incredible story is that of Enric Marco, a charismatic union leader and for years the president of the Spanish association Amicale de Mauthausen, dedicated to the memory of Holocaust victims. Marco turned out to be one of the greatest impostors in history, pretending to be a survivor of the Nazi extermination camp at Flossenbürg and becoming a highly visible and beloved figure among the Spanish public – at least until historian Benito Bermejo exposed his shameful deception.