US President Barack Obama on Friday honoured the Jews who fought and died in the 1943 Warsaw Ghetto Uprising against Nazi Germany, as he began a working visit to Poland.
An hour after landing in the Polish capital, Obama laid a wreath at an imposing monument raised in 1948 near where the doomed fighters made their last stand in a hugely symbolic revolt.
He then bowed his head before the black granite memorial, as a Polish military bugler played the Last Post.
Obama was joined by Polish leaders and members of Poland's Jewish community including US-born Chief Rabbi Michael Schudrich.
He exchanged words with Holocaust survivors, stopping to embrace an elderly woman.
Pre-war Poland was Europe's Jewish heartland, with a community numbering some 3.2 million, or around 10 percent of the country's total population.
Polish Jews represented around half of the six million victims of the Holocaust.
After invading Poland in 1939, Nazi Germany isolated Jews in ghettos, before beginning a systematic campaign of mass murder.
On April 19, 1943, they began liquidating the Warsaw ghetto, where just 60,000 people remained after the vast majority of the 450,000 held there had died of hunger or disease or had been sent to death camps.
It was then that hundreds of poorly-armed paramilitaries rose up in Europe's first urban revolt against Nazi Germany.
Against all odds, they held out for three weeks, with the Nazis finally using fire and explosives to defeat them.
Many of those who managed to escape through the sewers went on to join the 1944 Warsaw Uprising.
Around 18,000 Polish fighters and 200,000 civilians died in that failed two-month revolt, in which Warsaw was all but razed by the Nazis.
Before visiting the monument in central Warsaw, Obama also paid tribute at Poland's Tomb of the Unknown Soldier, which honours those killed in conflicts across the centuries.
He was later due to head to a working dinner with more than a dozen presidents from Europe's ex-communist nations, before wrapping up his European tour Saturday with bilateral talks with Poland's leaders.