After its archaeological discovery, the Ara was reconstructed using the few original fragments available from various museums, substituting cement reproductions for the missing parts, and covering all with a protective transparent structure.

Along the via Salaria, one of the oldest Roman roads, used to transport salt from the Adriatic to the Tyrhennian Sea, one finds the Catacombs of Priscilla, founded by a group of Christians belonging to a senatorial family.
Only the first of the two levels, the older one, can be visited. This small space contains one of the first representations of the Madonna and Child, from the second century. After traversing the long tunnels, one arrives at the Greek Chapel, named for the Greek writing on the walls. It is divided in the middle by an archway covered with frescoed scenes from the Old and New Testaments.

These are the largest catacombs of the city. They originated as private tombs of the second century and become the official tombs of the Roman bishops in the third century. They extend over four floors, but the visit is limited to the second. Burial recesses carved into the rock line both sides of the corridors. Some recesses that were created to hold many bodies, for many members of the same family, have also been excavated. Via a fourth century ladder, one reaches the Crypt of the Popes, one of the oldest nucleuses, where various pontifical martyrs, recorded in the Greek inscriptions, were buried. In the crypt alongside this one finds the tomb of Saint Cecilia, martyred at the beginning of the third century. Her remains were transferred to the Church of Saint Cecilia in Trastevere. The cubicle is decorated with frescoes from the fifth to ninth centuries.

These are the only catacombs to have stayed open in every era and therefore they are in bad condition. They were excavated on four levels, but the first is partially destroyed.
The visit begins on the second floor, where one finds the crypt of Saint Sebastian, containing the bust of the saint, attributed to Bernini. Interesting also are the remains of a third-century environment called "Triclia," where three funeral niches were posed one above the other. The walls are covered with drawings that represent Peter and Paul. Near the entrance to the galleries is the Church of San Sebastian, founded in the fourth century and rebuilt in the seventeenth century by Ponzio and Vasanzio. Inside, a single nave with three side arches and a ceiling made of wood one finds the statue of Saint Sebastian, the work of Antonio Giorgetti.

Begun by order of Vespasiano in 72 A.D., on the site of the Domus Aurea of Nero, the great amphitheatre was finished by his son Titus, eight years later. It was called Colosseum because of the gigantic statue of Nero that was erected nearby, with the help of 24 elephants.
It is the greatest monument of antiquity: elliptical in shape, with a circumference of 527 meters, the major axis of 188 meters, the minor one of 156 meters, the maximum height 57 meters. The total length of the stands is 30,000 meters, the seats numbered 68,000, standing places 5000.
The public entered the arena, divided into four levels, through four entrances and 80 arcades, numbered progressively. Entrance was free for everyone, but the places were subdivided according to the census: for senators were reserved the places nearest the arena.
Thousands of men and animals were massacred there solely for the pleasure of the crowd massed in the stands. In the fifth century the emperor Onorius prohibited the gladiatorial games and successively the Colosseum belonged to the Frangipane, who used it as a castle-fortress, and then to the Annibaldi. In 1312 Henry VII gave the amphitheatre back to the city. In 1451 the pope took away part of the building materials for the stairway at Saint Peter's and the door at Ripetta.
Within the amphitheatre there were houses, shops, a cemetery, a church, a theatre, and a hospital. From the highest levels one has a beautiful panorama of Rome, especially of the Forum.

Ruins of the old residence of Nero, built after the fire of Rome in 64. After his death successors dismantled or covered up the constructions, erecting new buildings in some areas. Trajan had his baths built and walled up part of them to serve as his library. Nero's house was called "aurea" (golden) because its facade was in fact covered with gold. The floor plan was rather complex and the internal decorations were of an incredible luxury. Alcoves, courtyards, a temple dedicated to water spirits with mosaics of Polyphemus, beautiful rooms such as the Octagonal Room, surmounted by a dome, and the Room of the Golden Vault, have all come to light.

In front of Termini Station and in the underground passageways, one can see the few remains of these ancient walls, built in the fourth century B.C. Compared to the Aurelian Walls, they enclose a much more limited area.

Formed as a sovereign and independent State after the Lateran Accords of 1929, stipulated between Italy and the Holy See, Vatican City extends over an area of 44 hectares, along the right bank of the Tevere between the eastern peaks of Monte Mario and the western peaks of the Gianicolo. It includes the piazza, San Peter's Basilica (see chart) and the palace of the Vatican.

The Argentine Tower is a building from the fifteenth century built by Bishop Burckhard of Strasbourg, then head of the diocese of Argenturatum, from whence comes its name.
In the broad zone of the Argentine, four temples from the republican period were found during the excavations of 1926 to 1930: temple A, on a rectangular plan, was erected in the third century B.C.; temple B, on a circular plan, is the most recent of the four, built in 101 B.C. by Lutazio Catullus; temple C, the oldest, was built in the third and fourth centuries B.C.; temple D dates to 200 B.C. and is thought to be dedicated to Lari Permarini. To the west of this zone is the Argentine theatre, whose facade dates to the eighteenth century.