 Complete the following phrase:  Marker had been working on a film about Chile with ISKRA since 1973. Marker had collaborated with Belgian sociologist Armand Mattelart and ISKRA members Valérie Mayoux and Jacqueline Meppiel to shoot and collect the visual materials, which Marker then edited together and provided the commentary for. The resulting film was the two and a half-hour documentary La Spirale, released in 1975. The film chronicles events in Chile, beginning with the 1970 election of socialist President Salvador Allende until his murder and 