Ceremonies were held in Poland today to mark the 70th anniversary of the outbreak of the Second World War. At dawn on September 1, 1939, the German battleship Schleswig-Holstein fired a broadside against the Polish city of Danzig, where it was moored on a friendship visit. Today’s ceremony, however, has been marked by renewed tensions between Poland and Russia, which have their root in part over differing interpretations of the Second World War. The Soviet Union occupied eastern Poland two weeks after the German invasion, according to the terms agreed upon by the secret Nazi-Soviet non-aggression pact. The Soviets later murdered 20,000 Polish.