Testaccio is the most Roman neighbourhood in Rome, and the least visited — a working quarter built on a hill of its own rubbish, where the food is the whole point. The rubbish is two thousand years old and made of pottery; the food is cucina romana in its purest, most stubborn form.
Start under the Piramide di Caio Cestio, the marble tomb a magistrate built himself around 12 BC. Slip into the Cimitero Acattolico beside it — cats, cypresses, and Keats under a stone that refuses to name him. Then west along Via Galvani to Monte Testaccio itself: thirty-five metres of broken amphorae, the spoil-heap of Rome's river port, with the shards still legible in the cuttings.
The market is the middle and the meal. The Nuovo Mercato rehoused the old stalls in 2012; go to Box 15 for the allesso panino and eat it standing. From there it's the slaughterhouse, the offal tradition it gave the city, and Volpetti on Via Marmorata for cheese to carry home. Piramide is two minutes on, the way you came.