Watch Forgotten Tragedy: The Story of the St. Francis Dam (2018) : Full Movie Online Free The largest man-made disaster of the 20th century, now largely lost to history. A journey through the early history of Los Angeles and the city's water needs. Ever-growing demand led to larger and larger projects, and eventually to tragedy. The history of the tragedy, the role of William Mulholland in the disaster and the city's water development, and how the lessons of the tragedy reflect on our current infrastructure needs today.