Arch of Janus

A four-faced marble arch from the early 4th century AD, in the ancient Forum Boarium (the Roman cattle market) near the Tiber. It's one of very few surviving four-faced (quadrifrons) arches anywhere in the Roman world — the design probably allowed merchants and traders to shelter at this busy crossroads. Steps from the Mouth of Truth and the temples of Hercules Victor and Portunus, it's an easy combined stop in this small concentrated zone of well-preserved monuments.