The Via Egnatia is one of those almost legendary Roman roads, not unlike the Via Appia. In fact, the Egnatian road is a continuation of the Via Appia: anyone leaving Rome to visit the East, would first travel to Brundisium, cross to Dyrrhachium (modern Dürres), and travel along the Via Egnatia to Thessalonica, to Amphipolis, Philippi, and Byzantium. On many places, the road still exists, although the modern Greek highway with the same name is a more recent project.
The interesting milestone above, which can be seen in the splendid Archaeological Museum of Thessaloniki, correctly records a distance of 260 miles to Dyrrhachium (CCLX, first line), the builder of the road, praetor Egnatius (second line), and his proconsular powers (third line).
A new page about this road, which was once used by the apostle Paul, is now here.