Why was rome described as the warehouse of the world?

Answer 1

Rome developed a huge empire and grew into the largest city in the world. She imported huge amounts of grain to feed its large population. Large quantities of olive oil and wine were also imported. Many luxury goods and stones for construction were imported, too. By being such a massive importer, Rome was the hub of the thriving trading networks which extended throughout the Roman Empire and beyond.

Oil and wine were carried in amphorae. To dispose of the vast quantities of amphorae, the Romans built a hill made of amphora shreds