Google just released thousands of new 3D buildings for the city of Rome -- enabling you to explore the blending of the ages in layered construction of Rome from within Google Earth, announced Mason Thrall, Program Manager, Geo 3D.
Rome really is an eternal city. There is much more to explore in Italy's modern capital, With a history spanning over 2500 years and regimes from the early kingdom, through the republic, the empire, and later as the heart of the Catholic faith in the Vatican city, each has made their mark on the current urban architectural landscape of Rome. And also, don't forget, the ancient Rome in 3D which allows you to see Rome as it was in 320 AD.
Alternatively, you can download this KML tour from the Google Earth Gallery to take a virtual tour of the 3D landmarks for yourself.