Thoughts about the big world powers

I'm nearing the end of my whirlwind tour of the history of the "west" (currently in the middle of World War II), and thinking about what makes a country powerful.

The British Empire lasted nearly 300 years (if you count it as starting with Elizabeth I) but only really took off after the Civil War in the 1640s and 50s.

The American Empire, the USA, had what is called "The American Century" in the 20th century, after experiencing a devastating Civil War in the 1860s.

Now we hear, "Last century was the American dream. This century is the Chinese dream" from people who are very likely to know, like Jean-Christophe Iseux.

Funny, China had a Civil War in 1949!

It seems to be a trend, but what it means I have no idea. It was also interesting to note in Watts Wacker's latest newsletter that the fastest growing economies in the world were mostly in Africa. Countries that have suffered through civil war and poverty for years. Here's a quote:

The fastest growing economies in the world? ... #1 - Equatorial Guinea +16%, #2 - Azerbaijan and Chad +14%, #4 - Angola +11.9%, Iraq, Sudan, Algeria, China and Kazakistan round out the top nine ... is Africa making a comeback?

It's all so fascinating, but I don't have a clue what it all means. Any thoughts from the geopolitical thinkers out there?