In this episode Alberto Angela celebrates Rome's Christmas by accompanying viewers on a fascinating journey through the wonders of imperial Rome: the Rome of the Caesars. Starting from the Mausoleum of Augustus - just reopened to the public after a restoration lasting 14 years - we retrace the fundamental stages that characterized the birth and expansion of one of the greatest empires of all time and we discover how and why the city of Rome in that period reached its maximum splendor.