How They Built the St. Francis Dam — And Why It Killed 431 People (1924)

In 1924 the most trusted engineer in California walked into a desert canyon north of Los Angeles, pointed at the ground, and said build a dam here. Nobody argued, nobody inspected his work, and nobody had the legal power to stop him. Four years later that same wall failed in the dark and killed at least 431 people. This is the story almost no one tells, not how the St. Francis Dam fell, but how it was actually built, decision by decision, by the machines and the men who raised it. Every documentary takes days of research. You can help us keep going by leaving a small donation, just click the link and support us: https://buymeacoffee.com/Construction... We follow the construction from the very beginning, the self taught chief engineer William Mulholland, the shallow keyway cut by steam shovel, the unwashed creek gravel that went into the concrete, the cable towers and sluicing troughs that poured the wall layer by layer, and the two fateful height raises that were never matched by a wider base. We also look honestly at what the records do and do not tell us about the equipment, and why the famous Hoover Dam cableways have nothing to do with this story. Finally we trace how this disaster forced California to write the dam safety laws that still protect millions today. This is heavy construction history told straight, with the engineering left in. TIMESTAMPS 00:00 The engineer no one was allowed to question 06:58 The canyon, the camp, and the rock no one read 09:28 The batch plant and the unwashed creek gravel 11:38 The cable towers that poured a 200 foot wall 17:46 Raised twice, never widened: the fatal decision 31:26 The collapse and the laws written in its aftermath SOURCES & FAIR USE Based on the engineering and historical record, including the work of J. David Rogers and Charles Outland, the 1928 Coroner's Inquest and Governor's Commission findings, the Association of State Dam Safety Officials, and the Santa Clarita Valley Historical Society archives. Archival images and footage are used for educational and historical commentary under fair use. All material is presented for documentary and educational purposes. SUBSCRIBE for more heavy construction history:    / @constructionlegends   Watch the full video here:    • How They Built the St. Francis Dam — And W...   #StFrancisDam #ConstructionHistory #Mulholland #EngineeringDisaster #DamFailure #CivilEngineering #1920s #California #IndustrialHistory #Documentary