Roman Forum of Zadar is the largest on the eastern side of the Adriatic sea, founded by the first Roman Emperor Augustus, as shown by two stone inscriptions about its completion dating from the 3rd century.
Ancient Zadar (or Iadera as the Romans would say) was a Roman colony from 48BC until the disintegration of the Roman empire in the 5th century. After a violent earthquake in the 6th century, the buildings surrounding the forum were destroyed. The still standing elements and stones (then used to rebuild) were retrieved for various buildings.
Most striking is the decorative column marking the western side of the forum. Notice the chains still visible on the column. During the Middle Ages it was the 'pillar of shame' used to punish evildoers.
Continuing on the western side of the Forum, you come to the remains of the Capitolium which was an important temple consecrated to Jupiter, Juno and Minerva.
To round out an appreciation of Roman Zadar, take a look at Zadar's Archaeological Museum which displays artifacts from the Roman period as well as a scale model of the original Roman forum.
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.