Ara Pacis:  See Wikipedia for a brief description. (Lungotevere in Augusta, at Via Tomacelli) -- Daily 9:30 am - 7:30 pm.  Now enclosed in a purpose-built structure by New York-based architect Richard Meier.

  Capitoline Museums:  The museum is divided between the Palazzo Dei Conservatori and the Palazzo Nuovo.  The second-floor picture gallery (pinacoteca) holds Renaissance painting from the 14th to the 17th century.An overview is provided by Wikipedia.  The Capitoline Museum is the oldest public museum in the world.  The first room includes ancient sculpture donated to the city by Pope Sixtus IV in 1471.

  Casa de Chirico: M, Th, F, Sat -- enry by guided tour -- 10:30 am, 11:30 am, 2 and 3 pm.  Advanced booking is essential.  The 4th floor of the building was Chirico's home for 30 years until his death in 1978.

  Catacombe di Priscilla: (Via Salaraia) Tues. - Sun 9am - Noon and 2-5 pm  Charge.  Bus to Via di Priscilla or Viale Liibia.  Just outside Villa Ada, the Catacombe di Priscilla are among Rome's most extensive early Christian burial complexes.  Far less busy than Appian Way catacombs.  Highlights include the so-Called Greek Chapel, whose frescoes -- painted between 2cd and 4th centuries CE and showing the Adoration of the Magi, Daniel in the lion's den, the resurrection of Lazarus, Noah, and the sacrifice of Isaac -- are more impressive than those of any other catacomb.  See also Wikipedia.

  Colosseum:  For an overview, see Wikipedia.  The Explore Italian Culture web-site has a section on Roman Colosseum -- How To See The Secret Parts.  The combined ticket with the Forum and Palatine Hill is valid for 2 days.  Holders of the Archaeologia Card, Roma Pass or Omnia Vatican, and Rome Pass are allowed to use a different queue.  To avoid the worst of the crowds, it's best to pre-book tickets, and come first thing in the morning or last thing in the evening.  Night tours are available (M, Th, F and Sat. 8:10 pm  - Midnight.

Ludus Magnus: (Piazza del Colosseo) -- Tunnels open to group only.  To the east of Colosseum, the sunken brick ruins at the foot of the Via di San Giovanni in Laterano are what's left of the Ludus Magnus, the main training school for gladiators.  It is connected to the Colosseum by tunnels, some of which still exist.

  Cripta dei Cappuccini:  The crypt of the Cappuchins in Rome includes 3,700 in various tableaux.  See also Wikipedia.

  Galleria Borghese:  For an overview, see Wikipedia.  The gallery includes a fantastic array of Bernini sculptures together with superb collections of Renaissance paintings.

  Church Of The Gesu:  (Via degli Astalli)  M-Sat. 7:30 am - 12:30 pm; 4 - 7:30 pm; Sun. 7:45 am - 1 pm and 4 - 8 pm Free.  The first Jesuit church built in Rome, it includes the tomb of St. Ignatius and the arm of St. Francis Xavier.  The Rooms of St. Ignatius are just next to the entrance of the church.  They include amazing false perspective artwork by Borromini.  St. Ignatius lived here from 1544 until his death in 1556.  M - Sat 4-6 pm; Sun. 10 am -Noon.

  Monte Testaccio:  Rome's mountain of pot shards.  See Wikipedia for a description.  Open by appointment only (tel: 06-0608).

  Museo Nazionale:  Wikipedia has an overview of this multi-branch Rome museum.    One ticket gives entry to the five branches.  See Tripadvisor on Palazzo Altemps, for one branch of the museum.  The Palazzo Massimo makes up with the Palazzo Altemps the greatest part of the museum.  Other branches include the Terme di Diocleziano and the Crypta Balbi.  You can buy a ticket form any location that then is valid for 3 days to visit the other branches.  The Crypta Balbi might be temporarily closed.

  Palatine Hill:  Wikipedia has an overview of the historic hill.  The Villa Di Livia may be the most impressive site on the hill. Wikipedia offers a brief introduction to the Villa of Livia.  The House of Augustus is also described by Wikipedia.  One ticket includes entry to the Palatine Museum, the House of Livia, the Roman Forum and the Colosseum.  Access is from the Roman Forum or from Via di San Gregorio, near the Colosseum.  Daily 9 am - 1 hour before sunset.  From the Arch of Titus, the uphill path takes you to the Palatine Hill, where the city was legendarily founded by Romulus.  Continue down the staircase to where the House of Augustus and Livia are believed to have been located and you come to the central area of the palace structures.

  Palazzo Barberini:  See also Wikipedia.

  Pantheon:  The Pantheon is by far the most intact of Rome's ancient monuments.For a detailed introduction, see Wikipedia.  Daily 9 am - 7 pm.  The Pantheon also houses the tomb of Raphael.  There is an Elephant Statue just behind the Pantheon.

  Roman Forum:  An introduction is provided by Wikipedia.  Via Sacra dog-legs through the core of the Forum.  The Lapis Niger, the "Black Stone" in front of the Curia, marks the traditional site of the tomb of Romulus.  The steps beneath lead down to a monument that was considered sacred ground during classical times.

Santi Cosma e Damiano: The Temple of Romulus in the Roman Forum, converted into the entrance vestibule of the church of Santi Cosmaie Damiano in the early 6th century.  Today it is entered from the Via dei Fori Imperiali (the discrete entrance is to the left of the Forum entrance), by way of a quiet Renaissance cloister.  The exquisite mosaics in the apse are amongst the oldest works of Christian art in the city, dating from the early 6th century.

  Saint Peter's Basilica:  Wikipedia offers a full description.  Daily: 7am - 7 pm.  Treasury: 8 am - 7 pm, Charge.  Dome: 8 am - 6 pm, Charge.  The queues can be long unless you get here before 9 am or after 5 pm.  An entrance off the south aisle, under a giant monument to Pius VIII, leads to the Treasury Museum.  You can get up to the roof and dome by taking the far right-hand gate of the portico of the basilica, following the signs for the "Cupola>'  It is fairly claustrophobic.  The Vatican Post:  Head to one of the post offices to the left of St. Peter's or behind the right-hand colonnade (M - Sat 8:30 am - 6:30 pm), or inside the Vatican Museums.  The pre-Constantinian necropolis can by visited by appointment or visit the Excavations Office on the right of the colonnade.  Public audience with the Pope is usually Wed. at 10:30 am and in the Piazza on Sunday at Noon.

  San Pietro In Vincoli:  See Wikipedia for an overview.  Sacred Destinations has a brief description.  Highlights include the chains of Peter below the high altar and Michelangelo's Tomb of Pope Julius II.

  Santa Maria del Popolo: Daily 7 am - Noon and 4 - 7 pm.  This church holds some of the best range of Renaissance and Baroque art of any Roman church, with works by Raphael, Bramante, and Caravaggio.  Originally erected in 1099 over the burial place of Nero to sanctify what was believed to be an evil place (the emperor's ghost had appeared here several times.  It took its present form in the 15th century.  There are two pictures by Carabaggio in the left-hand Cerasi chapel of the north transept: the "Conversion of St. Paul" and the "Crucifixion of St. Peter."

  Vatican Museums:  The Vatican Museums has an On-Line Ticket Office. See Wikipedia for a description of the museums.  M - Th. 8:30 - 6:30 pm; F - Sat. 8:30 am - 10:30 pm.  If the Pinacoteca is on your list, it's best to visit it first.  Turn right at the top of the stairs.  The Museo Pio-Clementino is home to some of the Vatican's best classical statuary.  #64 bus runs from Termini to St. Peter's.  Bus #40 terminates by Castel Sant'Angelo.  By metro, St. Peter's is a 5-minute walk from Ottaviano Station.  By foot, it takes about 20 minutes to walk from Piazza Navona to St. Peter's.  The best route is across Ponte Sant'Angelo.  See the official Vatican Site for tickets.

  Villa Giulia:  Described as Italy's most important museum of Etruscan Civilization.  Wikipedia provides an introduction to the museum.  Tues. - Sun. 8:30 am - 7:30 pm.  The western edge  of the Villa Borghese, the Villa Giulia is 5 minutes' walk away from Via Flaminia.  It is the world's primary collection of Etruscan treasures along with the Vatican's.