Tens of thousands of people joined striking Hungarian teachers in the capital Budapest to demonstrate against the government's education policies.
It was the biggest anti-government rally for two years.
The protesters are demanding an end to the centralisation of education, more curriculum choice for schools, better conditions for teachers and fairer pay.
The latest opinion poll suggests strong support for the teachers, even among voters of the governing Fidesz party.
The government, in power since 2010, has pledged to address some of the teachers' main concerns, including the centralisation question and increased bureaucracy.
Head teacher Istvan Pukli told a crowd outside parliament that the strikes would continue until "this government understands that it cannot go against the country".
He urged "everyone who is interested in the future of their children'" to support the protests.
Another one-hour demonstration is planned for 30 March unless the government makes concessions.
The last time such large numbers of people took to the streets of Budapest was inNovember 2014 when scores of protesters denounced Prime Minister Viktor Orban for allegedly employing corrupt officials and being too close to Russia.