Wearing yellow ribbons on their lapels to signify support, they filled the length of the Avenue Marina that runs from the beach to Barcelona’s iconic Sagrada Familia church, while the jailed leaders’ families made speeches.
A new regional election will be held in Catalonia on December 21.
Catalan President Carles Puigdemont rejected Madrid’s decision, to be implemented this week, and thousands of pro-independence protesters marched in Barcelona on Saturday.
Late Tuesday, Catalonia’s leader, Carles Puigdemont, said that the region will declare independence in a matter of days.
The referendum, declared illegal by Spain’s central government, has thrown the country into its worst constitutional crisis in decades.
Catalonia’s top court on Friday issued a warning to seven newspapers not to publish campaign notices for the referendum, a court spokesperson said.
City police said that around one million people took part in the police, one of the highest turn-outs in recent years.
Madrid’s conservative government has said it will block any further attempt to hold a referendum and has blocked previous secessionist challenges.
The rally was scheduled to coincide with Catalonia’s national day ‘La Diada.’