The Roman amphitheatre in Windisch was built in the first half of the 1st century AD in the immediate vicinity of the Roman legion camp Vindonissa. It is the largest ancient amphitheatre in Switzerland.
During the reign of Emperor Tiberius (14 to 37 AD), when the Legio XIII Gemina was stationed in Vindonissa, a first wooden amphitheatre was built. It was destroyed by fire around 45 AD.
The camp was rebuilt of stone around 50 AD by Legio XXI Rapax and it has been preserved until today. The outer wall was 111 × 99 meters, the arena 64 × 52 meters. There was space for around 11,000 spectators.
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.