The Ancient Agora of Classical Athens is the best-known example of an ancient Greek agora (central public space in ancient Greek city-states), located to the northwest of the Acropolis and bounded on the south by the hill of the Areopagus and on the west by the hill known as the Agoraios Kolonos, also called Market Hill. The Agora's initial use was for a commercial, assembly, or residential gathering place.
Agora contains several remains of ancient temples and buildings. Temple of Hephaestus is one of the best-preserved Greek temples, built around 450 BCE. The excavations has uncovered most of the over 30 known major buildings from the Agora, along with thousands of artifacts. Conservation efforts have restored thousands of pieces of pottery and amphora (the standard storage vessel of the ancient world), studied thousands of marble statues and reliefs, and analyzed the remains of human and animal bones to give us a better understanding of what life was like in the ancient Athenian world.
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.