Commemorations are being held to mark the 75th anniversary the Warsaw Ghetto uprising, when thousands of young Jewish fighters took up arms against occupying Nazi German forces during World War II.
The uprising broke out April 19, 1943, when about 750 Jewish fighters armed with pistols and other light arms attacked a German force more than three times their size.
Many left last testaments saying said they knew they would not survive but that they wanted to die at a time and place of their own choosing and not in the gas chambers at the Treblinka death camp, where more than 300,000 Warsaw Jews had already been sent.
Only a few dozen fighters survived when the Germans crushed the uprising. Most have since died or are no longer healthy enough to attend the observances.
Polish President Andrzej Duda is scheduled to visit a Jewish cemetery in the morning and then take part in the official ceremony at the Ghetto Heroes Monument.
The commemoration comes at a time of heightened tensions between Poland and Israel over Warsaw's new Holocaust law, which came into effect last month and led to harsh criticism from Israel, Jewish organizations, and others.
The legislation penalizes statements attributing Nazi German crimes to the Polish state with fines or a jail term. Polish government officials say the law is meant to protect the country from false accusations of complicity.
Poland was invaded by Nazi Germany in World War II and ceased to exist as a state. An estimated 6 million Poles, about half of them Jews, were killed.