In the election, Poles voted heavily for Solidarity candidates over communists in a clear sign that they wanted a change of power. That vote accelerated the fall of communism in Poland later in 1989, and fueled the wave of revolutions in eastern Europe over the following year or two.
"Poland showed to Europe and to the whole world that you can build a democracy without violence or bloodshed," European Council leader Donald Tusk said during ceremonies in his hometown of Gdansk. Tusk was a Solidarity activist and served as Poland's prime minister from 2007-2014.
But leaders from Poland's right-wing Law and Justice government stress that the 1989 elections were flawed as they stemmed from a deal that allowed the communists to preserve some influence under democracy.
That argument holds little sway with the government's opponents who argue that under Law and Justice hard-earned changes are now under threat, notably the country's relationship with the European Union.
Many of the government's opponents, who include Tusk and former president Lech Walesa were celebrating the milestone with a debate, a ceremonial declaration and a cake in Gdansk, the cradle of the pro-democracy Solidarity movement in the 1980s.
"We would not be celebrating democracy today if it had not been for those elections," Walesa said. "The people in power now should also remember they would not be there if not for that victory." Tusk encouraged a wide union of opposition forces to defeat the ruling party in the fall parliamentary elections. Last month's elections to the European Parliament gave victory to Law and Justice, because the opposition "wasn't united well enough or broadly enough," Tusk said.
"You can always count on me," he said, which some understood as a readiness to return to Polish politics. The ruling Law and Justice party was holding observances in Warsaw that included a ceremonial session of the Senate, attended by President Andrzej Duda, and public concerts.
They argue that Poland's transition to democracy and economic development could have been more rapid had the communist legacy been cut at the start. A key component of the government's political strategy is to discredit and remove from public life people who, they say, were linked to the communist and the early post-communist era, including Walesa.