"Si, se puede" - yes, we can. It was the rallying cry for thousands of "Indignado" protesters who flooded Spanish streets in 2011, and the far-left Podemos party spawned by that movement is now poised to enter parliament on the same slogan.
As Spain battles an economic crisis, polls suggest Podemos could come in third or fourth place when the country votes in a general election on Sunday, taking about 60 seats in the 350-seat assembly.
The grassroots Indignado movement brought thousands of Spaniards to Madrid's central Puerta del Sol square on May 15, 2011, furious over growing inequality, spending cuts and corruption.
More camps sprouted across the country - and as the movement gained momentum, it helped inspire the "Occupy" anti-capitalist protests that swept the world that year, from New York to London.
Podemos was founded in January 2014 with the goal of turning the Indignado movement - also known as 15M after its founding date - into a more structured political organisation. But the party has not forgotten its roots.
"Without 15M, there would be no Podemos!" Carolina Bescansa, a sociology professor who was one of Podemos' founders, told some 10,000 supporters gathered at a sports hall for an election rally in the working-class Madrid neighbourhood of Usera.
Candidates backed by the party won power in a cluster of town halls in local elections in May, including Madrid and Barcelona.
"Yes we can," Barcelona mayor Ada Colau, a former anti-eviction crusader, told the rally in Usera, holding back tears.
Citing new measures to help the soaring number of Spaniards lagging behind on their mortgage payments - adopted in part due to pressure from Podemos activists - Colau declared: "Look how we have changed this country."
Back in 2009 at the height of the financial crisis, she said, there were many who felt that all the options facing them were bleak - "Throw themselves out the window, or leave the country."
Among those listening from the bleachers were Serena, 39, who left her job as a financial analyst to become a teacher; Tristan, a 29-year-old Starbucks employee with a degree in art history; and Edurne, a 37-year-old secretary.
After the rally the three talked about May 15, 2011 in Madrid the way others recalled the fall of the Berlin Wall in 1989 - times that felt truly historic.
"Everything felt very free," said Serena. "Everyone sat down and said out loud what they were thinking."
Tristan Duanel said there had been "an effervescence" at the Puerta del Sol camp, which started as a small sit-in and grew over a month into a tent city with a market, nursery, garden and even a library.
"A colleague told me, 'You've got to see these people,'" he recalled, speaking of the Podemos founders.
Edurne Lopez said he had been at "almost all the protests,".
'Era of change'
Since the protest camps disbanded, voter anger has been channelled into Indignado neighbourhood associations and parties like the environmentalist Equo, left-wing Izquierda Unida, and the newly-formed Podemos.
"We are living an exceptional moment," said Juantxo Lopez de Uralde, a former head of the Spanish branch of Greenpeace, who is running for Podemos in the northern Basque Country.
"Whoever wins, things will never be the same - Podemos has opened an era of change."
Pablo Simon, professor of political sciences at Madrid's Carlos III University, said Podemos had "changed all other parties" by forcing greater transparency and by insisting that candidates charged with graft be banned from standing for office.
The changing political landscape has also paved the way for the rise of new centrist party Ciudadanos, he added.
Founded in the northeastern region of Catalonia in 2006, the party has seen its support rocket since deciding to go national last year.
While many voters share Podemos' diagnosis of Spain's problems, they do not agree with its solutions and in Ciudadanos they have found an alternative.
Like Podemos, it is expected to do well in Sunday's general election, putting an end to three decades of dominance by Spain's two main parties, the Popular Party and the Socialists.
"Podemos showed it is possible to vote for new parties," said Simon.
The party has also introduced a new way of doing politics, with a more relaxed style, heavy use of social networks, smaller meetings with voters, and creative ads financed by its supporters.
A recent spot features Darth Vader slashing his Popular Party membership card to move over to the "side" of the Indignados.
By Michaela Cancela-Kieffer
Make sure to follow The Local's election live blog on Sunday evening for all the latest on the Spanish elections.