The first prominent use of the tactic in United States of America occurred at the Pentagon, in Washington, D.C., on 17 October 1988, although anarchists had been using similar tactics in small numbers in preceding years in places like San Francisco, culminating with several hundred anarchists in black smashing glass store fronts and attacking vehicles in the Berkeley Anarchist Riot of 1989.[18][19] In D.C., over one thousand demonstrators—a small number consisting of a black bloc—called for the end to U.S. support for right wing death squads in El Salvador.[20] A black bloc caused damage to property of GAP, Starbucks, Old Navy, and other retail locations in downtown Seattle during the 1999 anti-WTO demonstrations.[21] They were a common feature of subsequent anti-globalization protests.[22]

(http://www.autoadmit.com/thread.php?thread_id=5780684&forum_id=2#49309383)