Lest you think knots are unworthy of serious study, I'll point out that
Vaughan Jones studied knots and braids, and he is a Fields Medal winner, the equivalent of the Nobel prize for mathematics. I've heard him speak about his knot studies, and the topic is
knot as simple as it might first seem. It turns out to have applications in areas such as biology, not just mathematics.
I'd tell you more, but my mouse cord is getting tangled.