15 October 2011 global protests - Wikipedia
As a continuation of the 2011 Spanish Protests, the largest protests took place in Spain, where more than a million people took the streets on 15 October, including 500,000 in Madrid, 400,000 in Barcelona, and 150,000 in Zaragoza. In Madrid, protesters reoccupied the Puerta del Sol square where the Indignados had camped five months earlier on 15 May.