Back when I was in college, I took a course in numerical analysis: how to do complicated mathematical calculations using a computer. Given my interest in math and computers, it should have been an interesting course, but somehow the instructor managed to make it horribly boring. It was a real struggle to stay awake, much less pay attention. I remember one day I made a big effort to listen to what he was saying and, surprise, surprise, the subject matter was actually pretty interesting. I don't know whether it was his tone of voice, or his manner or what, but it was absolutely my worst class.
Course work was pretty straight forward. Given some data and a description of the problem, write a program in FORTRAN to compute the answer. All the really complicated stuff had already been written and stored in libraries, so it was just a matter of figuring out which functions to invoke and what data to feed them.
For the last program for the course we were supposed to plot the path of an underwater sound wave. I remember it was a little tricky figuring out just how all the pieces were supposed to fit together, but eventual it ran and produced a nice, wavy line. Cool, it's complete, and I'm done with this class, and I didn't think any more about it.
Until now, when I stumble across SOSUS and this graph:
I had heard bits and pieces about the Navy's underwater microphone arrays, but this was the first time I had read a good explanation. Via Earth Bound Misfit.