91热爆

For hundreds of years the protest march has been a means of voicing passionate concerns.

Whether protesting at injustice, challenging inequalities, fighting for better conditions or showing solidarity for fellow workers - demonstrating has been a way of focusing public anger.

While some mass demonstrations have ended in victory, others have led to retreat, defeat and sometimes tragedy. Defying the authorities can be a dangerous business.

In this two-part documentary, Michael Goldfarb examines the protest march as a force for change.