The Via Egnatia, the great Roman road that linked Rome (via Brindisi and Dyrrachium on the Albanian coast) to Constantinople, cut directly through the middle of Philippi. The paved section that runs through the site is a few hundred metres long and is the original stone, with the wheel ruts of two thousand years of cart traffic still visible.
This is the road the Apostle Paul walked when he came to Philippi in the year 49 AD. It is also the road the armies of Brutus and Cassius marched to the battle in 42 BC. Standing on the paving stones is one of the more direct historical experiences you can have on this site.