Monte Testaccio

One of Rome's strangest and most overlooked archaeological wonders — an artificial hill rising 36 metres above the Testaccio neighbourhood, composed entirely of the broken terracotta amphora shards used to transport olive oil to ancient Rome. Between roughly 140 BC and 250 AD, around 53 million amphorae were emptied, systematically broken, and stacked here in an orderly fashion by the workers of the nearby Emporium (Rome's ancient port facility). Today the hill is a quiet, grassy mound — you can walk around it freely. Its unusual interior is honeycombed with caves cut into the sherd layer, many of which serve as the wine cellars and nightclubs of the Testaccio nightlife district (the clubs are built into the ancient pottery heap). A completely unique piece of urban archaeology that most tourists walk past without realising.