In 2017 I was pretty sure that the Oroville Dam would fail. This monster dam holds back Lake Oroville, which during a non-massive drought is California's second-largest reservoir, and cascading failures of spillways was dramatic!
This event started a fascination with the history of dam disasters and engineering. Los Angeles' St. Francis Dam is a tragic story of incredibly bad engineering. Hero of LA's water wars, and self-taught civil engineer William Mulholland drastically underbuilt a dam in a geologically terrible location. Just hours after declaring the dam sound, Mulholland and the world learned it had failed, killing hundreds of people in a 50+ mile river of destruction. California developed a lot of strict rules and regulations for dams, but in 2017 disaster was on the brink.
The dam held and has been repaired, Practical Engineering does a great job looking at the massive book of analysis conducted post-mishap.