The Port Wall in Chepstow is a late thirteenth century stone wall, which was constructed for the twin purposes of defence and tax collection by permitting users of the town's market only one point of access through the wall at the Town Gate. The wall originally formed a semi-circle extending for some 1,100 metres, roughly southwards from Chepstow Castle to the River Wye. It enclosed an area of 53 hectares, including the entire town and port as it existed at that time. Substantial sections of the wall remain intact.
References:
The ancient Argos Theater was built in 320 BC. and is located in Argos, Greece against Larissa Hill. Nearby from this site is Agora, Roman Odeon, and the Baths of Argos. The theater is one of the largest architectural developments in Greece and was renovated in ca 120 AD.
The Hellenistic theater at Argos is cut into the hillside of the Larisa, with 90 steps up a steep incline, forming a narrow rectilinear cavea. Among the largest theaters in Greece, it held about 20,000 spectators and is divided by two landings into three horizontal sections. Staircases further divide the cavea into four cunei, corresponding to the tribes of Argos A high wall was erected to prevent unauthorized access into the theatron and may have helped the acoustics, but it is said the sound quality is still very good today.
Around 120 CE, both theaters were renovated in the Roman style.