The Giant's Ring is a henge monument at Ballynahatty, near Shaw's Bridge, Belfast. It dates from the Neolithic period and was built around 2700 BCE. It is near the Shaw's Bridge crossing of the River Lagan, a point which has been used as a crossing of the river since at least the Stone Age. The original purpose of the monument was most likely as a meeting place or as a memorial to the dead.
The site consists of a circular enclosure, 180 m in diameter and 2.8 hectares in area, surrounded by a circular earthwork bank 3.5m high. At least three of the five irregularly spaced gaps in the bank are intentional and possibly original. East of the centre of the enclosure is a small passage tomb with a vestigial passage facing west. There were reports of other tombs outside the enclosure, but there is no trace of these.
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.