Commissioned by entrepreneur and engineer Giuseppe Mannajuolo, this distinguished palazzo was built between 1910 and 1911. It's one of the city's finest examples of Italian art nouveau architecture, known as stile Liberty (Liberty style). The building's western facade is especially impressive, its alternating convex and concave elements crowned by a faux dome. The star attraction, however, is the building's cinematic indoor staircase, a jaw-dropping elliptical creation adorned with wrought-iron parapets and embossed marble steps.
Note that this is a private building, and while visitors are welcome to view the staircase, they are not allowed to climb it.