In Physics, it is almost impossible not to make use of History timelines for the sake of understanding the evolution of ideas. But that's that.
I think some course in the History of Science would be highly valuable in STEM. Philosophy of Science would also be very beneficial.
There are many writings by Bertrand Russell that would fit in Math courses and that have a lot to do with Philosophy and that are very pertinent to any math student.[1][2]
In my opinion, one of the books that better makes the bridge between the Humanities and Science is Florian Cajori's History of Mathematical Notation. No only it is a very interesting book, shedding light at the intimate relationship of our symbol lexicon, our skills at abstraction and the progress in Mathematics, but it also teaches about cuneiform writing, rhetorical Math teaching in ancient Egypt, and how fundamental the invention of typography was for the stability of Mathematical notation.
A Professor I once knew lend me his only copy just because I mentioned the topic, and after skimming through I knew I had to buy my own. (For all of those of have lent books, you must know how much of a gamble it is, specially when the person you're lending the book is some random student!)
[1] Introduction to Mathematical Philosophy (http://people.umass.edu/klement/russell-imp.html)
[2] On Denoting (http://bactra.org/Russell/denoting/)