Porta Appia

Porta Appia was a landmark in Rome. It was a gate located in the southeast of Rome and considered to be one of the most important gates in the city.

Database Entry
''A south-easterly entrance to Rome. Porta Appia was one of the largest and most important gates to the city. As a result, it received two separate fortifications and renovations in its early life. From here, the Via Appia heads south through Italy.''

Source

 * Assassin's Creed: Brotherhood