A black bloc is a name given to groups of protesters who wear black clothing, scarves, sunglasses, ski masks, motorcycle helmets with padding, or other face-concealing and face-protecting items. The clothing is used to conceal marchers' identities, and hinder criminal prosecution, by making it difficult to distinguish between participants. It is also used to protect their faces and eyes from items such as pepper-spray which law enforcement often uses. The tactic allows the group to appear as one large unified mass. Black bloc participants are often associated with anarchism.
The tactic was developed in the 1980s in the European autonomist movement's protests against squatter evictions, nuclear power and restrictions on abortion, as well as other influences. Black blocs gained broader media attention outside Europe during the 1999 Seattle WTO protests, when a black bloc damaged property of GAP, Starbucks, Old Navy, and other multinational retail locations in downtown Seattle.
This tactic was developed following increased use of police force following the 1977 Brokdorf demonstration by the German police in 1980, particularly aimed at anti-nuclear activists and squatters. Key areas for this development were Hafenstraße, Hamburg, and Kreuzberg, Berlin. These were social spaces occupied by dissidents who preferred to create their own social institutions based on communal living and alternative community centres. In June 1980, the German Police forcefully evicted the Free Republic of Wendland, an anti-nuclear protest camp in Gorleben, Wendland. This attack on 5,000 peaceful protesters led many former pacifists to become willing to use violent methods. By December 1980 the Berlin City Government organised an escalating cycle of mass arrests, followed by other local authorities across West Germany. The squatters resisted by opening new squats, as the old ones were evicted. Following the mass arrest of squatters in Freiburg, demonstrations were held in their support in many German cities. The day was dubbed Black Friday following a demonstration in Berlin at which between 15,000 and 20,000 people took to the streets and destroyed an expensive shopping area. The tactic of wearing identical black clothes and masks meant that the autonomen were better able to resist the police and elude identification. The German media labeled them der schwarze Block ("the black block").