To plan and carry out other works, Alessandro employed Quintiliano Raimondi for the theatre and orangerie (today known as the “Lemon-house”), and Giuseppe Jappelli, who was in charge of the entire south section of the grounds, which he transformed with avenues, small lakes, exotic plants and unusual buildings.

These included the Swiss Hut (later rebuilt as the Casina delle Civette), the Conservatory, the Tower and Moorish Grotto, and the Tournament Field.

[1] It is still not open to the public because the excavation of the catacomb has been questioned by many due to a Jewish religious law that states that all human bodies must remain buried at all times.

Other exhibits come from other Torlonia properties and include pieces of the villa's furniture that managed to survive the years of neglect.

Other exhibits include three plaster reliefs by Antonio Canova, a woman's head in the style of Michelangelo, several pieces of furniture, and a marble pediment taken from a tomb on the Appian Way.

A final section of the museum is the reconstructed Bedchamber of Giovanni Torlonia (1872–1938), with the pieces of furniture that were used by Benito Mussolini during the period he resided in the villa.

The Casina delle Civette (House of the Little Owls) results from a series of additions to the nineteenth-century "Swiss Cabin", which was originally intended as a refuge from the formality of the main residence.

The complex now consists of two buildings, the main house and the annexe, connected by a small wooden gallery and an underground passage.

In 1908, architect Enrico Gennari began to convert the small building into a residence with huge windows, loggias, porticos and turrets, decorated with majolica and stained glass.