This video says about itself:
21 October 2017
Thousands of pro-independence demonstrators gathered in Barcelona on Saturday (October 21) to protest Madrid´s decision to sack the secessionist leadership of Catalonia and force the region into a new election, saying it had to take these unprecedented steps to prevent Catalan independence.
Catalan president Carles Puigdemont joined the protests.
Puigdemont made a symbolic declaration of independence on Oct. 10, but on Thursday (October 19) he threatened to press ahead with a more formal one unless the [Madrid] government agreed to a dialogue.
Catalan media have said Puigdemont could decide to dissolve the regional parliament himself right after independence is proclaimed and call elections before the Spanish senate makes direct rule effective.
Under Catalan laws, those elections would take place within two months.
Translated from Dutch NOS TV today:
[Left-wing] Mayor Colau of Barcelona, who recently said that she was not in favour of calling for independence for Catalonia, is fully behind the demonstration. She described the deposition of the Catalan regional government as an attack on the rights and freedoms of all.
President Bartomeu of the Barcelona football club also supports the protest. He said that the club is unconditionally behind the democratic bodies chosen by the people.
The Catalan Socialist Party [the social democrat PSC, daughter party of the Spanish PSOE], which does not support separation from Spain, said they were unable to accept the hard implementation of Article 155 of the Spanish constitution [by the Rajoy government in Madrid].
Pablo Echenique, a spokesman for [Spanish left-wing party] Podemos, tweeted: “The most corrupt party in Europe, which has 8.5% of the vote in Catalonia and is going to govern it. A terrible day for any democrat”: here. The Guardian estimates the number of Barcelona demonstrators today at 450,000.