Hundreds of thousands of people took to the streets of Madrid to protested against plans to cut public health care on Sunday.
The organizers of the rally said around 1 million people had gathered at Cibeles Square in the city centre, far exceeding the numbers who came to rallies against austerity programmes.
The Interior Ministry estimated the number of demonstrators at 250,000.
The event was held under the banner "Madrid rises up" and was organized by 74 groups including public campaigners and doctors' and nurses' associations.
Those at the rally chanted slogans such as "The united people will never be defeated" and carried placards with inscriptions such as "Stop health terrorism."
Shortages of staff have left more than 800,000 people in the city unable to be assigned a primary care physician in their health centres.
"The cuts that have been made since 2010 are destroying public health. We are all at the end of our tether, the situation is untenable," a doctor at the Hospital de la Princesa told dpa.
"Ten doctors are currently doing the work of 15," newspaper El País reported.
The rally included lawmakers from across the political spectrum as well as well-known artists. Alongside more investment, they also demanded the resignation of the regional head of government, Isabel Díaz Ayuso.
The regional government rejected the criticism, saying the protests are "politically motivated" ahead of regional and municipal elections scheduled for May 28 and the parliamentary elections at the end of the year.
Beyond Madrid, there have also been protests against health care cuts by patients and staff in other parts of Spain.
Some 20,000 people also protested in Santiago de Compostela in the Galicia region on Sunday, according to media estimates, while there were 11,000 in Burgos, some 250 kilometres north of Madrid, according to police.
