When I first started traveling a lot, there were so many things I didn't know about the world and how it was put together: what the heck a Gothic church was (I just knew goths wore black), how you should eat sashimi or, since I grew up in Australia, much at all about US presidents. Eventually, traveling taught me a lot about these things (and many more), but I know I could have got a lot more out of my trips if I'd given myself a few crash courses first.