Of all the Imperial Fora complexes, Trajan's was the grandest and most imposing, a veritable city unto itself. Designed by architect Apollodorus of Damascus, it comprised a vast basilica (at the time of writing closed for restoration), two libraries, and a colonnade laid out around the square, all once covered with rich marble ornamentation. Adjoining the forum were the Mercati Traianei (Trajan's markets), a huge, multilevel brick complex of shops, walkways, and terraces that was essentially an ancient shopping mall. The Museo dei Fori Imperiali (Imperial Forums Museum) opened in 2007, taking advantage of the forum's soaring, vaulted spaces to showcase archaeological fragments and sculptures while presenting a video re-creation of the original complex. In addition, the series of terraced rooms offers an impressive overview of the entire forum. A new, pedestrian-only passageway alongside Via dei Fori Imperiali also allows for an excellent, and free, view of the forum.
build a complex of this magnitude, Apollodorus and his patron clearly had to have great confidence, not to mention almost unlimited means and cheap labor at their disposal—this readily provided by captives from Trajan's Dacian wars. Formerly thought to be the Roman equivalent of a multipurpose commercial center, with shops, taverns, and depots, the site is now believed to be more of an administrative complex for storing and regulating Rome's enormous food supplies. They also contained two semicircular lecture halls, one at either end, which were likely associated with the libraries in Trajan's Forum. The markets' architectural centerpiece is the enormous curved wall, or hexedra, that shores up the side of the Quirinal Hill exposed by Apollodorus's gangs of laborers. Covered galleries and streets were constructed at various levels, following the hexedra's curves and giving the complex a strikingly modern appearance.
As you enter the markets, a large, vaulted hall stands in front of you. Two stories of shops or offices rise up on either side. It's thought that they were an administrative center for food handouts to the city's poor. Head for the flight of steps at the far end that leads down to Via Biberatica. (Bibere is Latin for "to drink," and the shops that open onto the street are believed to have been taverns.) Then head back to the three tiers of shops/offices that line the upper levels of the great hexedra and look out over the remains of the forum. Empty and bare today, the cubicles were once ancient Rome's busiest market stalls. Though it seems to be part of the market, the Torre delle Milizie (Tower of the Militia), the tall brick tower, which is a prominent feature of Rome's skyline, was built in the early 1200s.