Galleria Borghese
The museum for art lovers (you must have a reservation to enter!)
https://galleriaborghese.beniculturali.it
Vatican Museums
Don't miss: The Sistine Chapel, the Bramante Staircase at the entrance, the never-ending Gallery of Maps and, of course, Rafael's famous painting 'The School of Athens'.
St. Peter's Basilica
Take the elevator that takes you into the nave ...and on top of the basilica.
http://www.vatican.va/various/basiliche/san_pietro/index_it.htm
Colosseum
Circuit the Roman amphitheatre that once hosted bloody gladiatorial shows.
Roman Forum
Explore those ancient not so accessible ruins.
https://parcocolosseo.it/area/foro-romano/
Pantheon
Impressive dome with the central oculus.
http://www.polomusealelazio.beniculturali.it/index.php?it/232/pantheon
Palazzo Spada
Go to the courtyard to see the forced perspective gallery.
http://galleriaspada.beniculturali.it
San Pietro in Vincoli
Home of Michelangelo's Moses.
http://www.lateranensi.org/sanpietroinvincoli/
Bocca della Verità
You better speak the truth here.
Santa Maria della Concezione dei Cappuccini
The crypt is a macabre work of art.
Santo Stefano Rotondo
Church with gory frescoes portraying scenes of martyrdom.
Keyhole on the Aventine Hill
Go to the green door at the intersection of via di S. Sabina and via di Porta Lavernale and peek through the keyhole for a unusual view of...?
Capitoline Hill
To get a perfect, less bumpy view of the Roman Forum.
Victor Emmanuel II National Monument
Don't miss the viewing platform on top of this giant typewriter.
Fornaio
Authentic Roman bakery in Via Dei Baullari.
Frigidarium
THE BEST ice cream I have eaten in my whole life.
http://www.frigidarium-gelateria.com
La Locanda di Pietro
Try the 'Pizza revolution'.