The Vatican Museums
The Vatican Museums make up the richest and most extensive museum collection in the world. The Raphael Stanze and the Sistine Chapel are worth the price of entrance alone.
The most complete ancient Roman structure in the city, the Pantheon, finished around 125AD, is still to be marveled at for its enormous dome. Inside, you can visit the tomb of Raphael.
Porta Portese Flea Market
The Porta Portese flea market straggles all the way down Via Portuense to Trastevere train station, a riot of antiques, bric-a-brac, old clothes and pure junk.
The Church of Sant'Ignazio
In the centro storico, the church of Sant'Ignazio has a marvelous and often overlooked trompe l'oeil false cupola, covered in figures in various states of action and repose.
The Church of San Clemente
With a Mithraic temple in its lower levels, an earlier Christian church above, and a medieval basilica above that, San Clemente is Rome's unique history in microcosm.
The Galleria Borghese
Just opened after a drawn-out (even by Italian standards) refurbishment, the Galeria Borghese is one of the city's finest small collections, with a fantastic array of Bernini statues.
In the heart of the old city, Giolitti may be Rome's best place to enjoy great ice cream, with no fewer than seventy flavours on offer until 2am each morning.
Piazza Navona is perhaps the closest Rome has to a central square: go to be a tourist, stroll past the pavement artists and check out Bernini's typically grandiose Fountain of the Four Rivers.
The Church of Immaculate Conception
A must for fans of the macabre, the Church of Immaculate Conception has the bones of some 4000 Capuchin monks set out in patterns on the walls or simply left as skeletons and wrapped in their original gowns.