For example:
The various Villas and gardens Villa Celimontana, Villa Torlonia and Villa Ada, the non-catholic cemetery in Rome.
The 4 main basilicas of Saint Peter, Saint Paul outside the city walls, Saint John in Lateran and Saint Mary Major (for pilgrims and non pilgrims).

Galleria Borghese
2half hours tour Visit of this outstanding art gallery. You will admire the sculptures of Bernini among others the famous Apollo and Daphne, and paintings of Caravaggio, Titian, Raphael, and other famous artists. Reservation required.