Trajan's Market

Trajan's Market is a large complex of ruins in the city of Rome, Italy, located on the Via dei Fori Imperiali, at the opposite end to the Colosseum. The surviving buildings and structures, built as an integral part of Trajan's Forum and nestled against the excavated flank of the Quirinal Hill, present a living model of life in the Roman capital and a glimpse at the restoration in the city, which reveals new treasures and insights about ancient Roman architecture.Thought to be the world's oldest shopping mall, the arcades in Trajan's Market are now believed by many to be administrative offices for Emperor Trajan. The shops and apartments were built in a multi-level structure and it is still possible to visit several of the levels. Highlights include delicate marble floors and the remains of a library.

Source: Wikipedia