Mainz, known as Mogontiacum, was Rome’s most important city in Germania. In fact, the stage and auditorium of the Mainz theater was the largest anywhere north of the Alps. More than 10,000 audience members could be accommodated. The theater proportions were gigantic: The stage measured 42 meters wide. The audience area was 116 meters in width. The Roman Theater is located just above the Mainz-South Station adjacent the the “Roemisches Theater”-Station.
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.