Professor Alice Roberts looks at the rise of one of history's greatest civilisations, the Roman Empire, asking, what was the secret to its success? Experts explore the empire, investigating newly discovered battlegrounds in Britain and Spain to find out how Rome defeated her enemies, making her one of the world's first superpowers. Alice also discovers how Rome herself suffered military disaster in the forests of Germany, but how her eventual downfall was the enemy within – the decadence and misrule of the emperors that were Rome's real curse.