A busy thoroughfare, Piazza Bocca della Verità stands on what was once ancient Rome’s cattle market, the Forum Boarium. Little remains from that period except two tiny 2nd-century BC temples: the circular Tempio di Ercole Vincitore, the oldest marble temple in Rome, and the Tempio di Portunus, dedicated to Portunus, god of rivers and ports. Both are visitable by guided tour.

Just off the piazza, the 4th-century Arco di Giano is a four-fronted Roman arch where cattle traders used to shelter from the sun and rain. Beyond it is the Chiesa di San Giorgio in Velabro, a medieval church whose original 7th-century portico was destroyed by a Mafia bomb attack in 1993.