Emperor Augustus, after visiting the tomb of Alexander the Great in Alexandria, decided to build a magnificent tomb for himself and for his family in Campus Martius. The works started in 30 B.C. upon his return to Rome after the war against Anthony and Cleopatra that brought to the conquest of Egypt. The Mausoleum of Augustus is the largest circular-shaped tomb ever known with its diameter of about 87 meters. It consisted of an external pedestal, now completely lost, and of an internal cylindrical body from the center of which rose another cylindrical pillar bearing the bronze statue of Augustus on the top. Two obelisks were placed at the entrance of the mausoleum. Today they are situated in Piazza del Quirinale and in Piazza dell’Esquilino. The entrance to the mausoleum consists of a short staircase lined with two pillars that held bronze engraved tables reproducing Augustus’ autobiography. A circular-shaped cell with three rectangular niches is placed at the end of a long corridor, where the tombs of the imperial family were situated, and in the center a large cylindrical pillar contained a small square chamber: probably Augustus’ tomb. After being abandoned and despoiled during the Middle Ages, the mausoleum suffered several transformations. It was used by the Colonna family as a fortress (twelfth century), as a garden and as an amphitheater in the eighteenth century and lastly as a theatre and concert hall in the early twentieth century. In the years 1936-1938 the mausoleum was restored back to its original appearance in occasion of the demolition of the surrounding city quarter and the realization of Piazza Augusto Imperatore.