Caer Gybi in Holyhead contains the remains of a small Roman fortlet and naval base, whose atmospheric ruins can today be explored. Although the construction date of Caer Gybi is unknown, it is believed that it was built in the late 3rd or early 4th century. The structure was made up of three defensive walls with circular watch towers at each corner, while the fourth side fronted the sea and may have been a dock for the Roman warships that would have patrolled the area.
It is thought that Caer Gybi was constructed to defend against Irish sea raiders, and as a smaller fortlet was probably an outpost of the larger Roman fort at Segontium. It is believed that the Roman watchtower, which stood on the nearby Holyhead Mountain, served as the lookout post for Caer Gybi.
The Romans abandoned the region in the late 4th century, and by the 6th century the site had been given to Saint Cybi who founded a monastery within the walls. The medieval Church of St Cybi still stands there today.
Today, visitors to Caer Gybi can still view much of the original Roman defences, with walls standing up to 4m in places and at least one original corner tower.
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.