Roman Civilization
Christianity in the Roman Empire (Khan Academy)
Colosseum (Ancient History Encyclopedia)
Colosseum (Encyclopedia Britannica)
The Colosseum (National Geographic)
The Colosseum: Emblem of Rome (BBC History)
Roman Empire (Ancient History Encyclopedia)
The Roman Empire: Soldiers (PBS)
Secrets of the Colosseum (Smithsonian Magazine)
What was Life Like in the Roman Army? (BBC)
Why Ancient Rome Staged Epic, Violent Sea Battles (National Geographic Magazine)