Rome Has a Hill Made Entirely of Broken Jars

In the Testaccio district of Rome there is a low green hill about a kilometer around. Bars and garages are cut into its base. People walk dogs past it and buy groceries in its shadow. It looks like any city park mound, the kind a bulldozer pushes together when a new road goes in. Scratch the grass on the slope, though, and you don't find dirt underneath. You find pottery. The whole rise is made of broken jars, and Romans put every single one of them there on purpose.

A mountain of one-way containers

Monte Testaccio stands about 35 meters high. That's 115 feet, roughly a ten-story building. Its base covers something like two hectares, close to five acres, and archaeologists put the volume of material at around 580,000 cubic meters. Almost none of that volume is soil. It is the wreckage of oil jars, called amphorae, and the great majority of them came from one region: the olive country of southern Spain, shipped to Rome by sea and river to keep the city in cooking oil, lamp fuel and soap.

Forget the painted vases in museum cases. An amphora of this kind was a fat, thick-walled, plain clay drum that held about 70 liters, near 18 gallons of oil. It was freight packaging, closer to an oil drum than to a teapot, and nobody was meant to keep it. Olive oil soaks into unlined clay and slowly turns rancid inside the wall, so a used oil jar could not be safely filled a second time. Scrubbing didn't fix that. The smell was in the pot, and the pot was cheap.

Somebody engineered this garbage heap

Excavation showed the pile wasn't dumped. It was built. The mound rises in level steps, like a wedding cake, and diggers have traced at least four separate runs of terracing. Each step is held up by a retaining wall of nearly whole amphorae, stood in rows and packed tight with sherds so the wall wouldn't shift under load. Crews then tipped fresh breakage into the space behind the wall until it filled to the top, leveled it off, and started the next step higher up the slope.

The smell was a real problem, and they handled that too. Tens of thousands of freshly smashed jars, every one of them greasy inside, would have been hard on a whole working neighborhood. Workers appear to have scattered lime over the breakage as they went, which cuts the odor and helps bind the loose mass together. Empty jars were carried up the slope whole, broken where they were meant to lie, then dusted and packed into place. That is sanitation policy, not laziness.

The trash came with paperwork

Here is the part that rewrote history books. Huge numbers of these shards carry tituli picti, labels painted on by brush before the jar ever shipped. They are startlingly specific. One field gives the weight of the empty jar. Another gives the net weight of the oil poured into it. Others name the merchant, the men who weighed the load and certified it, the district back in Spain where the oil was bottled, and the year, given by the two consuls in office.

That turns a rubbish heap into a filing cabinet. The excavated layers date to roughly AD 140 to 250, though tipping may have begun a good deal earlier, and the hill was probably taller once than it stands now. Inside that window you can watch a supply chain actually running: which regions shipped, who signed for what, how the state checked that nobody shorted Rome on oil. Little else from the ancient world survives in this much administrative detail, and it only survives because it was garbage.