The Museum of the Walls (Museo delle Mura) is one of Rome’s free attractions. Situated in the imposing towers of the Porta San Sebastiano, it stands at the beginning of the Appian Way. It’s part of the Aurelian Wall circuit built in the 3rd Century by Emperor Aurelian to protect the city from increasing attacks.
The remparts give great views over the Appian Way and the Arch of Drusus.
Inside, there’s a small museum showcasing models of the wall circuit through the ages, as well as exhibition space. It’s also possible to walk inside the well-preserved walls and between the ramparts.
Getting there is easy via bus from the Colosseum, although the museum closes at 2pm each day.