Itinerary:

Ponte Sant'Angelo was completed in 134 AD by Roman Emperor Hadrian, to span the Tiber from the city centre to his newly constructed mausoleum, now the towering Castel Sant'Angelo. The statue of an angel was built on the top of the castel after the Pope Gregory I had a vision of Saint Michael the Archangel. The building was initially the Mausoleum of Hadrian then it was used by the popes as a fortress and castle, and is now a museum.
Piazza del Popolo is a large urban square in Rome. The name in modern Italian literally means "People's Square", but historically it derives from the poplars (populus in Latin, pioppo in Italian) after which the church of Santa Maria del Popolo, in the northeast corner of the piazza, takes its name.
Piazza Navona is a square in Rome, Italy. It is built on the site of the Stadium of Domitian, built in the 1st century AD, and follows the form of the open space of the stadium. The ancient Romans went there to watch the agones ("games"), and hence it was known as "Circus Agonalis" ("competition arena"). It is believed that over time the name changed to in avone to navone and eventually to navona.
Ponte Sisto is a bridge in Rome's historic centre, spanning the river Tiber. It connects Via dei Pettinari in the Rione of Regola to Piazza Trilussa in Trastevere. The construction of the current bridge occurred between 1473 and 1479, and was commissioned by Pope Sixtus IV (r. 1471-84), after whom it is named, from the architect Baccio Pontelli, who reused the foundations of a prior Roman bridge, the Pons Aurelius, which had been destroyed during the early Middle Ages. Currently traffic on the bridge is restricted to pedestrians.