Fodor's Expert Review Porta Maggiore
The massive, 1st-century-AD arch was built as part of the original Aqua Claudia and then incorporated into the walls hurriedly erected in the late 3rd century as Rome's fortunes began to decline. The great arch of the aqueduct subsequently became a porta (city gate) and gives an idea of the grand scale of ancient Roman public works. On the Piazzale Labicano side, to the east, is the curious Baker's Tomb, erected in the 1st century BC by a prosperous baker (predating both the aqueduct and the city walls); it's shaped like an oven to signal the deceased's trade. The site is now in the middle of a public transport node and is close to Rome's first tram depot (going back to 1889).