The big column in this photo is the Column of Phocas. Rick Steves calls it the "symbolic last nail in ancient Rome’s coffin." It was given in AD 608 to Rome by the Byzantine Empire to commemorate the Pantheon being converted into a Christian church. Most of the buildings in the Forum had already been leveled 200 years prior, and the last Roman emperor "left the building" in AD 476. The Dark Ages had already begun.