When it comes to alternative history, the Second World War is king. Dozens of books and wargames suggest how history would have changed if Hitler had invaded Britain or not invaded Russia. Want to know what happens when aNimitz-class supercarrier goes back in time to battle the Japanese fleet at Pearl Harbor? There's a movie for that. What would the world be like if Nazi Germany had won? Plenty of novels paint a dark portrait. Would the Third Reich have triumphed if it had developed jet fighters sooner? Such topics are like incendiary bombs on Internet chat forums.