Countries/Empires by population (1939)
1. British Empire: 550 million
2. Japanese Empire: 304 million
3. China: 267 million
4. United States: 147 million
5. French Empire: 105 million
6. Nazi Germany: 86 million
7. Dutch Empire: 78 million
8. Italian Empire: 56 million
9. Brazil: 40 million
10. Poland: 34 million
11. Spanish Empire: 26 million
British Empire pretty much stood alone against the might of Nazi Germany, Fascist Italy and the expanding Japanese Empire for a year (June 1940-June 1941) The British Empire in those nearly 2 years not only had to defend Britain from constant the German and Italian air force's but it also had to defend Britain's Asian colonies from the expanding Japanese Empire, despite fighting alone against three very powerful countries the British Empire won the Battle of Britain. British Empire was the most powerful in 1939, as if it wasn't then chances are Britain would've lost the Battle of Britain had it not been the most powerful at the time.
