Ponte Vella is a medieval footbridge built on Roman foundations in Ourense. At one time, it was considered to be the biggest bridge in all of Spain.
The original bridge across the Minho River was built during the first century rule of Emperor Augustus though other sources state that it was built during the Trajan period. A mention is made of this bridge in the will of Doña Urraca, where it is said that it was repaired with funds provided by Ferdinand III. From the Middle Ages, it has provided access to the city of Ourense for trade and pilgrimage.
The structure was rebuilt in 1230 by Bishop Lorenzo on Roman foundations (original piers), and repaired in 1449 by Bishop Pedro de Silva. It then measured 402 m long, with an arch span of 48 m. However, the main arch collapsed in 1499 and the bridge was rebuilt in 1679 to a length of 370 metres with seven arched spans, the main span measuring 43 metres.
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.