The original citadel of Argos, known as the 'Apsis' or 'Shield', which was on a rounded hill on the northeast of the ridge was supplanted by Larissa citadel.
On the southwest base of the rock a Mycenaean Necropolis was discovered, with 26 chamber tombs and six shaft graves, as well as a Middle Helladic building, and to the northwest is the Sanctuary of Apollo and Athena, in the shape of a long rectangle divided into four terraces with a court with a stone altar and statues .
A rock-hewn stairway leads to the temple of Apollo and a building of un-fired bricks on a stone foundation known as a Manteion, or oracle (the Greek verb 'mandevo' meaning, 'to guess').
A large church was built on top of this divinatory site. There are also a Round Temple and a Temple of Sharp-Eyed Athena.
The old 6th century BC Hellenistic acropolis at Apsis, at 100meters altitude, was built on the remains of an early Bronze Age settlement (around 2000 BC), the remains of its walls tracing an oval around the modern chapel of Aghios Ilias. There are two groups of pre-Mycenaean dwellings here as well.
The medieval citadel of Larissa (open Tues-Sun 8:30am-3pm;free) sits on a spit of rock 276meters high (905 feet). It was first built during the 6th century BC on 5th century BC foundations, an outer wall of Hellenic masonry added to the inner wall of the Archaic acropolis.
It was later added to by the Venetians and Turks), the earlier Byzantine medieval structure incorporating fragments from a Temple of Zeus Larisaos and a Temple of Athena.
With its massive walls, cisterns and wonderful views of the entire Argolid peninsula and the Gulf of Naufplio, it is well worth the climb via a steep path that begin behind the Theater, though there is also a car road.
The Archaeological Museum in the modern town house finds from excavations at Argos/Argolis, as well as from Lerna (open Tues-Sun 8:30 am-3pm, 2euros; 3euros for museum and theater).
It is off of Elgas Street between the market square and Platia Aghiou Petrou (the main church square). Its collection consists of Mycenaean tomb objects and armor, and pottery with the area's Roman occupation well represented in mosaics and sculpture.
The museum was built and organized by the French School of Archaeology with exhibits nicely presented and in chronological order. There is an impressive 8th century BC suit of armor with a crested helmet on display, of the kind that Homeric heroes wore and a 7th century BC fragment of painted pottery depicting Odysseus and his companions putting out the eye of the Cyclops (Polyphemus).
There is a pleasant garden with a portico with Roman mosaics of Bacchus, the Seasons, and hunting scenes.