The aim of the project was the renovation of a pavilion in the Concert Hall in the Postojna Cave deemed inappropriate functionally and material-wise. The design would provide for an exhibition and retail area and replace previously inappropriate visitor sanitary facilities located at the platform with new ones within the structure as well as connect them to a new biological treatment plant. Due to the conditions set by consent authorities, construction was possible only within the maximum dimensions of the partly demolished existing structure, while the specifics of construction in an underground cave required the use of inorganic construction materials appropriate for such conditions, adjusted to simple transport by the cave train and appropriate for manual fitting.

A part of the cave infrastructure, the exhibition and retail pavilion in the Concert Hall in the Postojna Cave is designed in two parts. The pavilion part is a transparent, passable area with four entrances/exits, designed within a longitudinal volume in the form of the letter S, thus reflecting the wall of the underground hall. The volume is structured in a manner that directs the flow of visitors and points to entrances and exits.

In the preserved and renovated service part of the structure, service areas and new sanitary facilities for the visitors of the Postojna Cave were provided as well as connected to the treatment plant on the level of the platform. The interior of the structure functions as a uniform, flexible space with installed floor plugs for plug-in exhibits and movable equipment. The volume of the exhibition and retail area is transparent throughout the entire interior height, functioning as an extension of the Concert Hall.

The structure is designed within the maximum dimensions of the previous structure in the form of the letter S, reflecting the preserved concrete wall and the wall of the underground cave.

The entire construction and fitting of construction elements observed nature protection requirements for the smallest impact on the value of nature possible. The concept of sustainability is also reflected in the heating system and ventilation and, last but not least, the first underground biological treatment plant in Slovenia.

The exhibition and retail area is flexible, as it is equipped with floor plugs prepared for plug-in equipment elements or exhibits. Separate lighting of individual points above the positions of floor plugs allows for various configurations and emphases in the interior.

The transparent facade is structured with four emphasised entrances/exits in relation to the direction of entering and the flow of visitors.

Both volume indents and facade elements are structured modular units.

The exhibition and retail area is flexible, as it is equipped with floor plugs prepared for plug-in equipment elements or exhibits. Other equipment elements in the exhibition niche can also be plugged in as desired to wall holders according to required exhibition or retail purposes.