More than a million people swamped Barcelona on Tuesday demanding independence for Catalonia from the rest of crisis-struck Spain, police said.
A human sea flooded the city, as Catalans waved red-and-yellow striped Catalan flags and marched for the region's national day, the Diada, many accusing Spain of dragging them into economic trouble.
"There are 1.5 million people and everything has gone peacefully," said a police spokesman.
Closely watched by other independent-minded regions in Europe such as Scotland and Flanders, the Catalans rallied under the slogan: "Catalonia, a new European state."
"What do the crowds want? A new European state. What do the people want? An independent Catalonia," they chanted, packing the northeastern region's capital in the warm evening.
"We are being pillaged and the money from our taxes is being lost to Madrid," said 21-year-old history student Eva Garcia.
"The economic crisis provides arguments for independence," added Mar Torres, a 24-year-old lawyer who came to the rally from Terrasa, some 40 kilometres (25 miles) west of Barcelona, with a group of friends.
About 1,000 buses ferried protesters from across the northeastern Spanish region.
The size of the turnout for the rally forced organisers to change the route.
"The Catalan people have responded magnificently," said Carme Forcadell, the president of the Catalan National Assembly, one of the organisers of the rally.
Fiercely proud of their distinct language and culture, Catalans increasingly feel they are getting a raw deal from Madrid and their president is now demanding the right to raise and spend their own taxes.
"If there is not an agreement on the economic basis, you know that the way of Catalonia for freedom is open," Catalonia's regional leader Artur Mas said in English at a news conference.
"My goal is to try to reach an agreement with the central government on the economic area and to try to protect Catalonia and to give our country the tools we need to build our future, our national future," Mas said.
Catalonia, whose economy is bigger than Portugal's, accounts for a fifth of Spanish output.
But it is being squeezed by austerity cuts and by an economic crisis that has put one in four people out of work across the country.
Mas, leader of the pro-autonomy Convergence and Union alliance, argues that the region gives far more to the rest of Spain than it receives.
The Catalan leader is to discuss the so-called fiscal pact with Prime Minister Mariano Rajoy on September 20.
"There is no battle more pressing, no challenge more important than attaining fiscal sovereignty for our country. And never more so than this very moment," Mas said on the eve of the march.
He said he could not join the march himself because of his "institutional" role representing all Catalans.
"Nevertheless, even being absent, I want you to know that your demands are my own, your voice is my own and your desires my own," Mas said.
Last month, the region reached out for a 5.0-billion-euro ($6.4-billion) central government rescue so as to make repayments on its 40-billion-euro debt, equal to a fifth of its total output.
But the Catalan government says the region is just asking for its own money back.
A survey taken in July and published in Barcelona-based newspaper La Vanguardia on Sunday showed 51.1 percent of people in Catalonia in favour of independence, compared to just 36 percent in 2001.
Rajoy and his conservative Popular Party government insist that fiscal autonomy for Catalonia will do nothing to resolve the economic crisis.
The only path, Rajoy says, is to slash the public deficit for the central government and in the regions, on which Madrid has imposed a deficit limit equal to 1.5 percent of economic output this year.
Catalonia posted a deficit of 3.9 percent of its output last year, contributing to the nation's overall deficit of 8.9 percent -- a figure that alarmed world financial markets.
"If at any time in Spain's recent history it has been important to work together for a goal, which is to improve prosperity and the well-being of citizens, to create jobs, to confront the crisis and to resolve it, I think that moment is now," Rajoy said at a news conference Tuesday.