Mesopotamia
This structure protected the northern border of China
The Great Wall of China
What title did the Roman emperors use?
Caesar
This river provided water and transportation
The Nile
Name one specific reason for the decline in Rome's empire.
food shortage; Marcus Aurelius's death; empire too big to feed everyone; personal armies; civil war/splitting of empire; inconsistent rule, etc.
This ruler made Christianity legal.
Constantine.