The Ateneum, a three-storey museum building evoking Neo-Renaissance style, dominates the southern end of Railway Square. Its main facade is articulated by densely spaced large window openings and a projecting central risalit decorated with allegorical sculptures. On the second floor of the central risalit are three busts depicting Raphael, Pheidias and Bramante – a painter, a sculptor and an architect – representing the three fundamental genres of visual art.
The pediment is supported by four caryatids which, on the basis of their attributes, can be interpreted as allegories of painting, sculpture and architecture. The fourth female figure possibly represents the decorative arts. A series of portrait medallions on the second floor of the main facade depicts prominent figures from Western art and famous architects.
The museum building is organised around a vestibule located behind the main entrance, from the centre of which a monumental staircase leads visitors to the exhibition spaces on the upper floors.