Metapontum was an important city of Magna Graecia, situated on the gulf of Tarentum, between the river Bradanus and the Casuentus (modern Basento). It was founded by the Achaeans of the Greek Peloponnese c. 720 BCE as part of the wave of Greek colonization from the 8th century BCE onwards across the entire region of southern Italy. Thriving on agriculture and trade, the city became one of the most prosperous colonies in Magna Graecia.
Today, the best surviving evidence of Metapontum's importance in antiquity is the 6th century BCE Temple of Hera with 15 of its Doric columns still standing. A theatre was built over the assembly place in the 5th century BCE which had half columns and a Doric frieze. The theatre was remodelled again in the mid-4th century BCE and in its current form measured 62 metres at its widest part and could seat some 8,000 people.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.