A black bloc (sometimes black block) is a tactic used by protesters who wear black clothing, ski masks, scarves, sunglasses, motorcycle helmets with padding, or other face-concealing and face-protecting items. The clothing is used to conceal wearers' identities from both the police and politically opposing organizations by making it difficult to distinguish between participants. It is also used to protect their faces and eyes from pepper spray, which is used by police during protests or civil unrest. The tactic also allows the group to appear as one large unified mass. Black bloc participants are often associated with anarchism, anarcho-communism, communism, libertarian socialism and proletarian internationalism. A variant of this type of protest is the Padded bloc, where following the Tute Bianche movement protesters wear padded clothing to protect against the police.
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.