The Roman amphitheatre is located in the ancient suburb of Neapolis, in what is now an archaeological park, near the Greek theatre and the Altar of Hieron. The amphitheatre is on a different orientation to these other structures and probably follows the lines of an urban plan developed in the late classical period, which is reflected by the street discovered near the Sanctuary of Demeter in the suburb of Achradina. The main road from Achradina to Neapolis led up to the amphitheatre through an Augustan period triumphal arch, whose foundations are still in situ. Between the arch and the amphitheatre, there was a monumental fountain, fed by a large cistern which has not yet been identified. A separate cistern provided water to the amphitheatre itself - it is preserved under the nearby church of San Nicola.
The amphitheatre is largely excavated out of the living rock and in the north east it takes advantage of the slope of the same rocky outcrop which the Greek theatre is built into. Almost nothing of the superstructure, which was built from masonry, survives.
There were two entrances and a complicated system of steps which led from the upper levels to the exterior. At the centre of the arena there was a rectangular pit, which was originally covered. An underground passage ran from this pit to the entrance at the southern end of the amphitheatre. This pit and passage were necessary for machinary used during the shows. The seating in the cavea is separated from the arena itself by a high platform, under which was a vaulted corridor through which gladiators entered the arena. Above this were the front seats, which were reserved for high ranking individuals. The inscriptions carved on the blocks of the railing were edited by Gentili and seem to have been intended to indicate the different seating areas.
Higher up, there are another two covered walkways running around the entire arena under the seating, while a third walkway ran around the top of the monument and may have had a colonnaded portico running around the top of it. From these circular walkways, a series of radial passages allowed access to the various sectors of the cavea.
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.