What's your favorite part about 20th century US History (the class and material taught in it, that is)?

I particularly liked the parts about the Industrial Revolution and the Great Depression. The Industrial Revolution is interesting in terms of technologies invented, what led up to its invention, and its impact. The Great Depression... I used to hate economics until I was about 14. Then I realized that it's rather interesting how everything works. Economics is the product of social psychology and applied mathematics, really. There's so much in economics to like. I don't want to be solely an investor, but I'm certainly going to make a lot of investments in the future. But the Great Depression is particularly interesting because of everything that led up to it, and the economics of everything is so interesting...