Greta Garbo is the title character in MGM's "The Temptress" from 1926 (released Oct. 3) — a Parisian femme fatale who drives men to homicidal madness. One suitor is the protagonist, Robledo (Antonio Moreno), who is in charge of a dam construction project in Argentina.
The dam shown is the St. Francis in Saugus, Calif. In an approximately 30-second sequence, we see four views of the St. Francis Dam under construction — in moving pictures.
Later in the film (shot at MGM Studios in Culver City), Robledo's main rival, Manos Duras (Roy D'Arcy), blows up the dam - a model of the St. Francis. A rainstorm ensues, and floodwaters breach what's left of the (fake) dam.
With a bit of artistic license, life imitated art less than two years later.
We must acknowledge author Jon Wilkman for bringing "The Temptress" to our attention in his 2016 book, "Floodpath: The Deadliest Man-Made Disaster of 20th-century America and the Making of Modern Los Angeles."
NOTE ABOUT THIS FILM CLIP: From the slate that reads, "He is coming!" at the 0:50 mark, we jump immediately to a later 11-minute sequence that covers the make-believe collapse and flood.