The Roman Odeon, the most significant ancient monument in Patras, is in the upper town and was built around 160 AD, in the reign of either Antoninus Pius or Marcus Aurelius. It was severely destroyed by successive invasions, wars, and earthquakes. It was almost buried under the remains of other buildings and ground. It was in 1889 when the Odeon was found by accident while some workers were digging up the ground for the construction of the port. It has been restored and partially reconstructed, and is used as an open-air theatre for performances and concerts in the summer.
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.