An artificial hill on the outskirts for he historical center, Testaccio or Monte dei Cocci (hill of terracotta shards) is composed of over 53 million storage amphorae of the Roman period. It is estimated that an additional 13 million amphorae were used in building works, used for target practice by the Vatican artillery and looted over the course of the centuries. The deposit dates from the 1st BC through 3rd century AD and extends over a kilometer in diameter and is 54 meters high. As indicated by stamps of the producers on the handles and painted inscriptions (tituli picti) as well as their Dressel forms, archaeologists can reconstruct the production, administration and distribution of their contents. The majority of the amphorae were for oil imported from Spain. North African forms are also present. It has been suggested that after being unloaded at the nearby port on the Tiber, the amphorae were systematically broken, stacked and sprinkled with lime. From the medieval period onwards the hill was the site of popular festivals. Today restaurants and wine bars incorporate windows into the hill into the decor.