A long time ago I started collecting exemplars of edged weapons (swords, knives, axes) for no reason other than I found the aesthetic interesting. But in collecting these things you may find, as I did, that just looking at them gets to be boring so you start reading about them. When was this kind of sword invented? Who used it? For what? What replaced it? What came before it? Etc.
Before too long you may find that you are looking at two parallel universes that are interlocked by expressions of intent. In one universe are people figuring out what makes metal have the properties it does and how can I change them? And the other universe is people looking at what metal can do "now" and applying it to their creative process in weaponry.
It is an amazing tapestry of complexity behind the simple appreciation of "that's a cool sword/knife"