"In 1937, he ventured into political protest, condemning capitalism in his production of Marc Blitzstein's The Cradle Will Rock, an opera about predatory bosses and downtrodden harlots in a grim industrial outpost called Steeltown. When police prevented the show from opening, Welles staged a popular uprising, led a march up Broadway, and presented a single, impromptu performance in a rented auditorium. The walls of the city should have tumbled down, as if besieged by trumpets."
via
http://film.guardian.co.uk/features/featurepages/0
,4120,1031003,00.html