The second world was the Soviet Union and its satellites, mostly the Warsaw Pact nations, China and Cuba. The third world was everyone else, and we don't use this term anymore because it lumps together a hugely diverse range of countries. We'll talk more about the specific economic and development challenges faced by the so-called third world countries, but the big one in terms of the Cold War was that neither the US nor the Soviets wanted any of these countries to remain neutral. Every nation was supposed to pick sides, either capitalist or communist, and while it seems like an easy choice now, in the 50s and 60s it wasn't nearly so clear. I mean, for a little while it seemed like the Soviets might come out ahead, at least in the third world. For a while, capitalism, and especially the United States, seemed to lose some of its luster. The US propped up dictatorships, had a poor civil rights record, we sucked at women's gymnastics, plus the Soviets were the first to put a satellite, a man, and a dog into space.