National Museum of the Palazzo di Venezia

More of an enormous traffic circle than a piazza, but a good central location. The centerpiece is the enormous Vittorio Emanuele Monument (aka the Wedding Cake or the Typewriter) with the Capitoline hill next door. Mussolini used to harangue Romans from the first floor balcony of Palazzo Venezia (see under Museums), to the west of the square.

This is one of the two main Jesuit churches in Rome, the other being the nearby Sant'Ignazio. The interior is Mannerist art on steroids. Simply astounding.

Good collection of Renaissance and Baroque art, including by Velasquez, Titian, Raphael, and Bernini, all owned by the Doria Pamphilj family. Excellent audio guides really bring the paintings to life.

Built in honour of Victor Emmanuel, the first king of a unified Italy, this vast structure may appear to be solid white marble but actually contains many rooms inside. There are two permanent museums, one on Italian Reunification and one on emigration from Italy, as well as other spaces that host rotating exhibitions. A walk through the Flag Room leads to the tomb of the unknown soldier. Good views from half-way up but you can also pay €10 (€2 concessions) and take a lift all the way to the top.

Ballroom-like church which crowns part of the Capitoline Hill. Don't be fooled by the plain stone exterior.

Built in the 17th century to a design based on an architectural sketch by Michelangelo. Highlights include the ancient Colossus of Constantine statue (the Colosseum was probably named for another giant statue, the Colossus of Nero which stood near the Flavian Amphitheatre as the Colosseum was originally known), The Dying Gaul, a magnificent marble sculpture that copies a bronze Greek original of the 3rd century BC and the Capitoline Venus. It also contains the remarkable original gilt bronze equestrian statue of emperor Marcus Aurelius (the one in the piazza is a replica).