He took us on an excellent tour the of the city dropping us at several key sites (including a shopping and restaurant area where we sat outside under a framework of vines eating pizza and drinking the local beer), before getting us back to the ship in ample time before we set sail.
One of the places we stopped was the Arch of Hadrian which was erected in honour of the Emperor Hadrian around AD 132. The arch was built over the line of an ancient road which ran from the Arcopolis and Agora to the Olympeion and South East Athens.
The arch itself is supported by pilasters which are crowned with Corinthian capitals, similar but almost twice as tall pilasters again with capitals frame the lower half of the structure. The arch is crowned by an arrangement of columns and beams with a central triangular pediment. I believe that this was a stand alone structure and was not part of a wall.
The structure is constructed from Pentelic Marble. This stone is sourced from Mount Pentelicus which is famous for its fine white marble and who's summit (3,632ft) is about 10 miles North East of Athens. In ancient times the peak had approximately 25 quarries on the southern slopes at elevations up to 3,300 ft.
There are two inscriptions on the arch, the one on the Western side which faces the Acropolis says 'THIS IS ATHENS THE ANCIENT CITY OF THESEUS' (Although there seems to be various similar interpretations). The inscription on the Eastern side says 'THIS IS THE CITY OF HADRIAN AND NOT THESEUS'
Photographed 5 June 2012.