Umbilicus Urbis Romae is otherwise known...
State of the center
Navel of the City of Rome
Kilometre Zero 
Center of the world
The Umbilicus Urbis Romae ( "Navel of the City of Rome") was the symbolic centre of the city from which, and to which, all distances in Ancient Rome were measured. It was situated in the Roman Forum. Originally covered in marble, the Umbilicus is now a forlorn-looking brick core some 2 metres high and 4.45 metres in diameter.
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State of the center
Navel of the City of Rome
Kilometre Zero 
Center of the world
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