Dubbed the “crystal rock” by the Dutch architecture firm, the facade of the Milestone building in the city of Esslingen in southern Germany will be formed from fritted glass containing photovoltaic cells that will reflect back images of the city.

Extruded and indented blocks on the square grid of the facade will give the building a 3D profile that the architects describe as a “pixelated map”.

Passersby will be able to use their phones to interact with the facade, which will be printed with QR codes that reveal information about the city.

“This building shows Esslingen to all people who pass by on trains and will become a new symbol to reflect its past heritage and future’’, said Winy Maas, MVRDV co-founder.

“The façade with fritted glass will have QR codes integrated on to it informing visitors about Esslingen’s people, landscape, and histories which makes the building an interactive library for all.”

The buildings’ volume is pushed inwards to create a fragmented façade, an ‘Esslinger grotto’ that reflects its actual topography and forms an open public walkway right through the centre, marking the location of the central district. On upper levels, offices are located and envisioned as light, attractive and flexible spaces that are customisable for different users to create combinations of work and life. On the ground level, the crystal rock façade opens up to the public square in front connecting the city to the building and provides public amenities including a café, restaurant and meeting areas.

The Milestone’s partly mirrored-transparent façade integrates technology and sustainability with the use of fritted glass to reduce overheating, PV cells to store and generate energy, and finally, QR codes which carry information about the city in a pixelated map spread across the building making it both visible and readable. The three-dimensional map is located on the lower part of the building extends to a height of 40 meters, and with stairs and terraces, it forms a publicly accessible core that tenants and visitors can walk up to take in views of the vineyards and surrounding hills. All of these sustainability features in the façade all the potential for the building to become partly self-sufficient in future.

The transparency of the façade allows an interaction between inside and out, whilst reflecting the daily interactions in the square thus turning the front of the building into a new meeting point. In contrast, at night, the building becomes illuminated through its façade and is a new beacon for Esslingen. For train travellers, the current beacon being a large chimney of a former knife factory with the abbreviation of the factory name on its side, spelling the word DICK, which means ‘big’ in German.

MVRDV was commissioned to work on the project by investors RVI and construction will start in 2020.