The recent bridge collapse in Miami is a tragedy, but I can guarantee this: as they investigate it, they will find not just one thing that led to the failure. They will find what I call a Cascade of events; at least 7. Any which of one, if corrected, would have prevented this from happening. And one of those Cascades will be human error.
Let me show you an event that happened almost 100 years ago and was one of the worst engineering disasters of the 20th Century. One that had the man who is praised as the man who brought water to Los Angeles at its center and destroyed him and killed hundreds of people.
It also might surprise people to learn this dam that failed? Another one with the exact same design is still in Los Angeles. Ponder that.