Via triumphalis, south side of the Arch of Constantine and Colosseum (exterior of the south side of the inner wall) seen from the foot of the Palatine hill.

The Arch of Constantine (Italian: Arco di Costantino) is a triumphal arch in Rome, situated between the Colosseum and the Palatine Hill. It was erected by the Roman Senate to commemorate Constantine I's victory over Maxentius at the Battle of Milvian Bridge in 312. Dedicated in 315, and the latest existing triumphal arches in Rome, it was also the only one to make extensively reuse major sculpture from earlier monuments. The arch spans the Via triumphalis, the way taken by the emperors when they entered the city in triumph.
The Via Triumphalis (Triumphal Way) route: The following schematic for the route taken by "some, or many" triumphs is based on standard modern reconstructions; any original or traditional route would have been diverted to some extent by the city's many redevelopments and rebuildings; or sometimes by choice. The starting place (the Campus Martius) lay outside the city's sacred boundary (pomerium), on the western bank of the Tiber. The procession entered the city through a Porta Triumphalis (Triumphal Gate), and crossed the pomerium, where the general surrendered his command to the senate and magistrates. It continued through the site of the Circus Flaminius, skirting the southern base of the Capitoline Hill and the Velabrium, along a Via Triumphalis (Triumphal Way) towards the Circus Maximus, perhaps dropping off any prisoners destined for execution at the Tullianum. It entered the Via Sacra, then the Forum. Finally, it ascended the Capitoline Hill to the Temple of Jupiter Capitolinus. Once the sacrifice and dedications were completed, the procession and spectators dispersed to banquets, games and other entertainments sponsored by the triumphing general.

more on https://en.wikipedia.org/wiki/Arch_of_Constantine , https://en.wikipedia.org/wiki/Roman_triumph#The_route