An opposition rally in Warsaw drew hundreds of thousands of people on Sunday, two weeks before an election that the liberal Civic Platform (PO) says may decide Poland's future in the EU and its democratic standing.
The nationalist Law and Justice (PiS) government could win the vote, opinion polls show, but may struggle to form a majority amid discontent over rising living costs and concern over an erosion of democratic checks and balances.
About a million people attended in the capital's biggest rally on record, Warsaw city authorities said.
Public broadcaster TVP, which independent media observers say has become a government mouthpiece under PiS rule, quoted police saying about 100,000 people had joined.
Online news channel onet.pl said that according to its calculations, between 600,000 and 800,000 people attended.
Some carried banners saying "PiSexit" or "The cat can stay", referring to the pet animal of PiS chairman Jaroslaw Kaczynski.
The opposition is hoping the march encourages voters to take part in the election, giving it a chance to come ahead.
"Big change is coming. This is a sign of Poland's rebirth," PO leader Donald Tusk told crowds gathered in a central Warsaw square, where many people waved Polish and EU flags.
Mr Tusk, a former European Council president, has said PiS could aim to take Poland out of the EU, which the party denies, and has described the election as crucial for minority and women's rights.
PiS, in power since 2015, has campaigned on a pledge to keep migrants out of Poland, saying it was key for national security, and to continue funnelling money towards families and the elderly.
"I want to be free, be in the EU, I want to have a say, I want to have free courts," said Hanna Chaciewicz, 59, dentist from Otwock outside of Warsaw.
PiS denies western criticism that it has subverted democratic norms and says its reforms of the judiciary are aimed at making the country fairer and free of vestiges of communism, while its changes to public media rid it of foreign influence.
But it has yet to gain access to billions of euros in EU Covid recovery funds, which Brussels has withheld over the court reforms.
"Everybody is investing in jobs, in fighting the climate catastrophe," Warsaw Mayor Rafal Trzaskowski, a senior PO member, told those at the rally.
"And we have been denied this money because someone has decided to destroy democracy in Poland."
