The Mausoleum of Augustus is a large tomb built by the Roman Emperor Augustus in 28 BC. The interior of the mausoleum is not open to tourists. The mausoleum was one of the first projects initiated by Augustus in the City of Rome following his victory at the Battle of Actium in 31 BC. The mausoleum was circular in plan, consisting of several concentric rings of earth and brick, planted with cypresses on top of the building and capped by a conical roof and a statue of Augustus. Vaults held up the roof and opened up the burial spaces below.
In the Middle Ages the tumulus was fortified as a castle and occupied by the Colonna family. After the disastrous defeat of the Commune of Rome at the hands of the Count of Tusculum in 1167, the Colonna were disgraced and banished, and their fortification in the Campo was dismantled. Thus it became a ruin.
It was not until the 1930s that the site was opened as a preserved archaeological landmark along with the newly moved and reconstructed Ara Pacis nearby. The restoration of the Mausoleum of Augustus to a place of prominence featured in Benito Mussolini's ambitious reordering of the city of Rome which strove to connect the aspirations of Italian Fascism with the former glories of the Roman Empire.
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.