Because filming about the Tlatelolco massacre was forbidden, the production had to make a fake documentary about urban redevelopment for a school; but the police arrived and while they were arguing the camera was filming. The police discovered they weren't filming for a school project, and the people living in the departments protected in their own homes the actors and the rest of the crew.
This movie had to be done underground, because there was a risk to be jailed for touching this topic.
The original title was "Bengalas en el cielo (Flares in the sky)".
The massacre of October 2nd. of 1968 was lived by many people and they wanted to make a movie about it. The government censored every record about that day. Without budget, with his life in risk, Héctor Bonilla got support from his friends to achieve the production.
The movie was forbidden around 6 months. The journalist, intellectuals, and Héctor Bonilla himself (who said that he would release free copies to the people) forced the government to let the movie be shown, only cutting the army scenes.