The Palazzo della Civiltà Italiana, colloquially known as the "Square Colosseum," is a defining monument within Rome's EUR district. Conceived as a centerpiece for the Esposizione Universale Roma (EUR), a large complex initiated by Benito Mussolini's government in 1935 for the planned 1942 World's Fair, its construction history reflects Italy's complex political transition. Designed by architects Giovanni Guerrini, Ernesto Bruno La Padula, and Mario Romano, its design was formally approved in 1937, with construction commencing in 1938. The building was inaugurated in an unfinished state in 1940, but the World's Fair was ultimately canceled due to World War II. The building consequently remained vacant for over a decade before first opening to the public in 1953.

Architecturally, the building is a prime example of the Rationalist and neoclassical style promoted. Its form is a large parallelepiped on a square base, entirely clad in travertine marble. The structure is distinguished by its six rows of nine arches on each of its four identical facades. The structure is supported by a reinforced concrete frame and stands on a tall stylobate. The structure's most striking feature is its repetitive geometric loggias, creating a total of 216 arches. This design was directly inspired by the ancient Roman Colosseum, intended to embody "romanità. At the four corners of the base stand equestrian statues of the Dioscuri, added in 1942 along with 28 marble statues representing various arts and human activities.

Following years of abandonment after the war, the building's function has been redefined in the 21st century. Since 2015, the Italian luxury fashion house Fendi has occupied the building as its headquarters, reportedly under a 15-year lease. While the interior is generally not publicly accessible, the exterior and its piazza remain a popular destination for visitors.