Sisterhood Tie to Mexico City Made Official. Los Angeles and Mexico City were officially linked as sister cities by the City Council Tuesday. But the action, by a 12-1 vote, was accompanied by an oblique slap at Mayor Sam Yorty for having proclaimed the relationship without prior council approval last year. Yorty will head a Los Angeles delegation flying to Mexico City today for a three-day fete in honor of the affiliation. As part of the ceremonies Friday, Yorty said, samples of lunar rocks brought back by Apollo 11 astronauts will be placed on public display at the Mexico City Anthropological Museum."I believe this is a dramatic way of highlighting the birth of this relationship, and I know that it will be recognized In Mexico as a symbol of the goodwill between their people and the people of Los Angeles and the United States", the mayor said. 

So - we see the main event at the museum as well as ceremonies indoors and outdoors, including some footage taken at/on the subway and a formal dinner.

This is likely the only surviving footage of this historic "Sisterhood Celebration" event outside of Mexico.  
Unable to gauge how long the film is...but there's quite a bit of historic material from an event that probably wasn't well-documented.