Spaniards angered by budget cuts and corruption scandals have assembled in cities across the country in a "citizens' tide" of protests.
Thousands converged in central Madrid on Saturday in a din of drums and whistles, in one of scores of demonstrations called by a grouping of civil movements.
Demonstrators converged on Plaza de Neptuno, near the lower house of the Spanish parliament - scene of a huge protest in September that led to clashes with riot police.
The protest movement chose February 23 for the demonstration since it marks the anniversary of an attempted coup in 1981 by right-wing officers who tried to crush Spain's young democracy and restore military rule.
The manifesto said the demonstrations targeted the "coup of the financial markets" which they largely blame for the crisis brought on by the collapse of the housing market.
The movement unites workers in various sectors such as teachers, nurses, doctors, students and miners, with groups such as environmentalists and small political parties.
|Saturday's protests coincided with a court appearance by the Spanish king's son-in-law to face fraud charges
Spain has been seeing weekly protests against the spending cuts and tax hikes imposed by Mariano Rajoy's conservative government to reduce the public deficit.
The cuts are affecting the public sector, while the current recession that started in late 2011 has shut down companies and thrown millions out of work, driving the unemployment rate above 26 percent.
Youth unemployment is even higher, hitting peaks of over 50 percent.
Rajoy defended his government's record during a state of the nation address in parliament on Wednesday.
"We have left behind us the constant threat of imminent disaster and we are starting to see the path for the future," he said.
In a parallel development on Saturday, protesters jeered the Spanish king's son-in-law before he was questioned by a judge on the Mediterranean island of Palma de Mallorca about allegations that he and a partner spirited away millions of euros through fraudulent deals.
Inaki Urdangarin, who has not been charged with a crime, made his way into the courthouse on Saturday amid tense street scenes where a contingent of around 170 police kept several hundred protesters away from the building.
Urdangarin, married to the 75-year-old King Juan Carlos' second daughter, Princess Cristina, has denied any wrongdoing.
The Duke of Palma, the title held by Urdangarin, had been called to answer questions behind closed doors about whether he used his prominent status to secure lucrative deals for a nonprofit foundation he ran and then fraudulently diverted money for personal gain.
The judge was to question Urdangarin about three alleged offences against the Treasury, including corporate tax fraud related to his foundation and matters linked to his personal income tax returns.
Urdangarin was also expected to be asked about alleged bank accounts in tax havens such as Andorra, Luxembourg and Switzerland.