Slovenian studio Korpnik Produkcija has completed a concrete observation tower overlooking the spa town of Rogaška Slatina, topped by an angular glass cafe resembling a crystal.

Designed by Celje-based Korpnik Produkcija with structural engineers Ponting, Kristal Observation Tower stands 106 metres tall and is currently the tallest building in Slovenia.

The studio said it is intended to be a "respectful" meeting point between the town's historic 19th-century spa complex and its more modern centre, where it is positioned.

"The architectural challenge was to hierarchically and respectfully connect the old city structure into a new modern urban whole," Korpnik Produkcija founder Nande Korpnik told Dezeen.

"This would also logically connect different architectural styles and designs from different time periods, in the successful coexistence of neo-historical, modern and contemporary architecture," he added.

At the base of the tower, a triangular concrete structure with a glazed entrance houses a visitor centre, shop and toilets alongside a lift and fire-escape stair.

The shaft of the lift has been fully glazed on the tower's eastern side, providing visitors with views towards the Zdravilske Park as they ascend.

At the top of the tower, the cafe and observation level are housed within a crystalline glazed form, designed to reference the region's long history of glassmaking.

A bar sits at the core of the cafe, surrounded by seating that offers views in all directions, and a circular window in the floor that provides views down to the tower's base.

The geometric concrete and glass forms of Kristal Observation Tower were chosen to ensure the tower did not appear to prioritise any one particular direction, offering views of both the historic and modern areas of the town.

"The building is designed in a geometrically expressive way, enabling an interesting play of different orientations and views and creating a dynamic and interesting appearance of the building," explained Korpnik.

"The base and entrance part is directed in one direction, while the glass head of the cafe and panoramic floor turns in the direction of the old city centre formed around the historical park," he added.

At the tower's peak is an open-air terrace, wrapped by a two-metre-high glass fence that allows for unobstructed 360-degree views of the surrounding landscape.

Other observation towers recently featured on Dezeen include the 65-metre-tall Port of Montreal by Provencher Roy, which features a cantilevering viewpoint, and a sculptural coastal lookout by Studio Moto.

The photography is by Miran Kambič.