For many its the Roman empire or the Greeks. Similarly ancient Egypt. Or the British empire. Maybe the Japanese, Chinese and Norse as the next 3.
I have deliberately not mentioned time periods there.
These are the most commonly beloved. What are your favourites and why?
I’m a huge WW2 enthusiast. It’s one of the very few things I can confidently say I know a lot about. And even then, I still learn new things about it from time to time.
Random interesting fact: In 1974 a wargame was conducted to see what might have happened if the Germans had actually launched Operation Sealion (the planned invasion of Britain in 1940). They found that it would have been a catastrophic defeat for Germany.