Marble Base in Roman Form
While labeled Milliarium Aureum, possibly Umbilicus Urbis
The Milliarium Aureum (‘Golden Milestone’) was erected in the Roman Forum (Forum Romanum) by Augustus when he was superintendent of the road system (cura viarum) in 20 BC. It was a gilded bronze milestone conceived as a point where all the roads converging on Rome. It has been suggested that it had names of major cities on it, though it is more likely that the names of road and praetorians acting as superintendents of the road were inscribed on it.
At the northwest end of the Forum Romanum is the base of a monument labeled Milliarium Aureum, but it is probably too large to be it. Instead it is more likely identified as the Umbilicus Urbis (the ‘navel of the city’) - the symbolic center of Rome. In 1959 excavations uncovered a circular concrete base in the area which is more likely to be the Milliarium Aureum. It served as the model for the Milion in Constantinople.
While labeled Umbilicus Urbis, possibly the Milliarium Aureum
First Milestone on the Via Appia
A New Topographical Dictionary of Ancient Rome by L. Richardson, Jr.