Close to a million people 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.

As AP reports, the rally's grassroots organizers called for 10 prominent members of the secessionist movement in the northeastern Spanish region to be freed from prison.    

Eight former members of Catalonia's dissolved Cabinet and two activists are in jail while Spanish authorities investigate their alleged roles in promoting an illegal declaration of independence last month in violation of Spain's Constitution.