It has been 80 years since the start of the World War Two, and world leaders among them German Chancellor Angela Merkel and U.S. Vice President Mike Pence are commemorating the day in Poland, where the conflict is still a live political issue.

Poland was in the center of the war where there was a trail of death and destruction. The country lost about a fifth of its population, including the vast majority of its 3 million Jewish citizens.

After the war, its shattered capital of Warsaw had to rise again from ruins and Poland remained under Soviet domination until 1989.

Ceremonies began early in the small town of Wielun, site of one of the first bombings of the war on Sept. 1, 1939, with speeches by Polish President Andrzej Duda and his German counterpart, Frank-Walter Steinmeier.

Parallel events, attended by Prime Minister Mateusz Morawiecki and European Commission deputy chief Frans Timmermans, were held in the coastal city of Gdansk, site of one of the first battles of the war.

Morawiecki spoke of the huge material, spiritual, economic and financial losses Poland suffered in the war.

“We need to talk about those losses, we need to remember, we need to demand truth and demand compensation.”

For Poland’s Law and Justice (PiS) party, the memory of the war is a central plank of its “historical politics”, aiming to counteract what it calls the West’s lack of appreciation for the extent of the nation’s suffering and bravery under Nazi German occupation.

PiS politicians have also repeatedly called for war reparations from Germany, one of Poland’s biggest trade partners and a fellow member of the European Union and NATO. Berlin says all financial claims linked to World War Two have been settled.