Hundreds of thousands of people marched through Madrid today in a show of strength by a fledgling radical leftist party, which hopes to emulate the success of Greece's Syriza party in the Spanish general election later this year.
Podemos supporters from across Spain converged around the Cibeles fountain before packing the avenue leading to Puerta del Sol square in what was the party's largest rally to date.
State broadcaster TVE said that hundreds of thousands were at the march, but no official attendance figures were provided.
Podemos (We Can) aims to shatter the country's predominantly two-party system and the March For Change gathered crowds in the same place where sit-in protests against political and financial corruption laid the party's foundations in 2011.
The party's rise is greatly due to the charisma of its pony-tailed leader, Pablo Iglesias, a 36-year-old political science professor.
Hailing from the Madrid working class neighborhood of Vallecas, Mr Iglesias prefers jeans and rolled up shirt sleeves to a suit and tie and champions slogans such as Spain is "run by the butlers of the rich" and that the economy must serve the people.
"We want change," Mr Iglesias told the crowd. "This is the year for change and we're going to win the elections."
Speaking at a meeting in Barcelona, prime minister Mariano Rajoy said he did not accept the bleak picture of Spain that Podemos propagated.
"They're a sad bunch, who go around saying how badly things are going," he said, giving them no chance of winning the elections.
"They're not going to do it."
Senior Podemos member Rita Maestre said their aim was to show that the party is the instrument for change.
"We called the demonstration in the hope of lighting the torch (flame)."
In roughly a year, Podemos has leap-frogged from being the dream of a handful of university professors and activists to a political party.
Opinion polls show the party could possibly take top spot in upcoming elections and thus trigger one of the biggest political shake-ups in Spain since democracy was restored in 1978 after decades of dictatorship.
"The two-party framework has suffered a change. It now really does seem like a third political force can achieve government, so yes, I think it can have a great impact," said literature student Alicia Sanchez, 20.
This year, Spain holds elections in 15 of its 17 regions this year followed by general elections.
Podemos' first battle will be in the southern Socialist heartland of Andalusia in March, followed by regional and municipal elections in the crucial ruling Popular Party stronghold of Madrid in May.
"The political class has lost all credibility," said unemployed lathe worker Marcos Pineda, 54. "The PP that governs today had its former treasurer in jail for corruption and the banks were bailed out with 40 billion euro of European money, but the government refused to call it a bailout."
Podemos has often expressed its support for some of the policies of left-wing governments in Venezuela, Bolivia and Ecuador, which makes many Spanish mainstream politicians bristle.
In Europe, it openly supports Syriza, which won national elections in Greece on January 25 and which has pledged to challenge the austerity measures imposed on the country by the European Union and International Monetary Fund.
While there are major political and economic differences between Spain and Greece, both countries have suffered severe economic crises, massive unemployment and austerity measures while simultaneously having to put up with myriad political corruption scandals.
This combination has given rise to a nationwide anti-establishment movement that has boosted Podemos and Syriza immensely.