http://agathe.gr/guide/northwest_corner_and_the_hermes.html
Northwest Corner and the Hermes The area of the northwest corner is where the Panathenaic Way, leading from the main gate of Athens, the Dipylon, entered the Agora square (Figs. 58, 59). This was accordingly ... Northwest Corner and the Hermes The area of the northwest corner is where the Panathenaic Way, leading from the main gate of Athens, the Dipylon, entered the Agora square (Figs. 58, 59). ... These took the form of rectangular shafts of marble with a set of male genitalia carved halfway up and a likeness of the god Hermes at the top. Several dozen examples of these very conservative monuments have been found in the excavations in this area, ranging in date from the early 5th century B.C. to the 2nd century A.D.