By Adam Easton
BBC News, Gdansk
**Leaders from Russia and Germany are among those expected at ceremonies in Poland to mark the 70th anniversary of the start of World War II.**At 0445 on 1 September 1939, the German battleship Schleswig-Holstein opened fire at point blank range on a Polish fort on the Westerplatte peninsula.
At the same time, the German Wehrmacht invaded Poland over three frontiers.
The attacks triggered Britain and France’s declaration of war against Germany two days later.
Although it can be argued the war in Asia started much earlier and many in the US date the start of the war to 1941, Germany’s invasion of Poland meant the war in Europe had begun.
Foreign leaders from 20 countries - including German Chancellor Angela Merkel and Russian Prime Minister Vladimir Putin - are expected in Gdansk on Tuesday afternoon for a ceremony beside a monument to the heroes of Westerplatte.
Important symbol
At 0445 (0345 BST, 0245 GMT), Polish President Lech Kaczynski and Prime Minister Donald Tusk will lead a domestic ceremony along with war veterans beside a monument to the heroes of Westerplatte in Gdansk.
Watching the start of World War II
Pact that set the scene for war
At the time of the attack by the Schleswig-Holstein - which was moored in the Polish harbour on a friendship visit - Gdansk was known as the free city of Danzig.
The 182 Polish troops defending the Polish fort were expected to resist for about 12 hours. Despite coming under fire from the air, sea and land, they held out against a force of more than 3,000 Germans for seven days.
According to a survey published on Monday, Westerplatte is the most important symbol of Polish resistance in the whole of the war.
Of the speeches expected throughout the ceremonies, it is Russian Prime Minister Vladimir Putin’s which is the most keenly anticipated in Poland.
According to the historian Professor Pawel Machcewicz, the Poles are expecting some sort of gesture from Mr Putin.
Thorny relations
Poland’s relations with Russia are currently thornier than those with Germany, partly because of differing historical interpretations of events at the start of the war.
Two weeks after the German invasion, the Red Army invaded and annexed eastern Poland under terms agreed in the secret protocol of a Nazi-Soviet pact.
In early 1940, the Soviet secret services murdered more than 20,000 Polish officers in the forests around Katyn. For 50 years Moscow blamed the Nazis and only admitted responsibility for the crime in 1990.
Russian courts have ruled that Katyn cannot be considered a war crime and Moscow is still refusing to declassify documents about the massacre.
The temperature was raised further this week with accusations broadcast on Russian state TV which implied the USSR was justified in its invasion of Poland because Warsaw had been conspiring with Hitler against Moscow.
Mr Putin is unlikely to defend this viewpoint, but nor is he likely to offer an apology for the Soviet invasion, although he may make a gesture to ease the tensions over Katyn.
In an article published in the Polish daily Gazeta Wyborcza on Monday, Mr Putin wrote: "The Russian nation, whose fate was distorted by the totalitarian regime, well understands Poles’ feelings about Katyn, where thousands of Polish soldiers are buried.
“We should remember the victims of this crime.”