By Matthew Cooper Manchester United legend Wayne Rooney is a secret history buff who is “obsessed” with second world war documentary series ‘The World at War’. Rooney’s interest in history has been revealed by football writer Henry Winter, who visited Auschwitz with the England squad ahead of Euro 2012 when Roy Hodgson’s men were based in Poland. During the trip, Rooney is said to have “asked the most perceptive questions” of the group’s tour guide. And when Winter asked how Rooney was so knowledgable about the second world war, the striker revealed he was “obsessed” with ‘The World at War’. T…