Revolution and Protest Online
Using the Advanced Search, in the Global Event field, select Chile for a selection of pamphlets, videos, and photographs about the Pinochet regime. Documents on Argentina's military dictatorship are also available, although the date-sorting is problematic.
ProQuest Historical Newspapers
Includes more than four dozen major U.S. newspapers, including the New York Times and the Chicago Tribune.
Nexis Uni and Factiva
These are databases of newspapers and other news sources around the world, from 1980 to the present. In Nexis Uni, use the Advanced Search; select the News tab; and type your search terms in Headline. In Factiva, the default date range is "Last 3 months," but you can change the date coverage if you need to. You don't need quotation marks for phrases. To find your search term in headlines, use the code hd (e.g., hd=peronistas).
Alexander Street World Music
A search for revolución brings up recordings like Cancion Protesta: Protest Song of Latin America. But it will probably be more effective to search for the names of composers, performers, and songs found in secondary sources like The Militant Song Movement in Latin America.
Latin America in Video
Original-language documentaries and feature films from Latin America (N.B. -- no subtitles; no useable transcripts)
For sources on protest murals, use the HOLLIS Advanced Search and search for the Subject "mural painting and decoration", adding the name of the country as a keyword.
News photographs from the Associated Press, spanning the 20th century. After searching, you can limit the Source Type to images only.