http://agathe.gr/guide/panathenaic_way.html
Panathenaic Way Numerous roads led in and out of the Agora square. By far the most important, however, was the broad street known as the Dromos or Panathenaic Way, the principal thoroughfare of the city ... Panathenaic Way Numerous roads led in and out of the Agora square. ... The street is unpaved except to the south, as it begins the steep ascent to the Acropolis, where it was paved with large stone slabs in the Roman period. Elsewhere it is made up of layers of packed gravel; at the north, some sixty-six superimposed layers were excavated, reflecting a thousand years of use of the thoroughfare, from the 6th century B.C. until the 6th century A.D. The line of the street was defined in the Hellenistic and Roman periods by successive open stone gutters along its south side (Fig.5).