Just read my text book today about the end of the first civilizations and the start of the classical era when states and empires in Eurasia and North Africa started to appear. One section really stood out to me because it's one of my favorite subjects in history is the collision between the Greeks and the Persians. Seeing how the Persian empires boarders went from Asia-Minor all the way to the Hindu Kush, how difficult it must have been to control that big of an empire and to keep all of those people under one rule, since most of them were of different cultures. Then the Greeks and their multiple city states, Sparta, Athens, Corinth, and many others stopped the Persians from conquering all of Greece, and we cannot forget Leonidas and the famous 300 Spartans and how they held off the Persians for so long. I didn't not realize though that it all started when the Persians conquered Ionia and the Ionians revolted and asked Athens to help them. Very interesting section indeed.