In Brazil, the government is cracking down on protesters who have been breaking the law. A mysterious masked group, who call themselves the Black Bloc, say they are fighting back against the government's violent reaction to protesters.

The Black Bloc's tactics, which often escalate to vandalism and destruction of public property, started in Germany and rose to prominence in Brazil during protests tied to the FIFA Confederations Cup.

Al Jazeera's Gabriel Elizondo reports from Sao Paulo.