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ASCENSION: Zagreb Observation Tower

Zagreb, Croatia (International Competition: Winner)


Zero-2-Infinity Observation Tower



Rian Architects & Designers’ winning proposal ‘Zero-2-Infinity’ Observation Tower envisions a new urban development connecting North to South Zagreb (Novi Zagreb). The competition site is the area near Hipodrom, and the floodplain area in front of the Hipodrom was selected for the design. The sculptural structure of the tower which touches the maximum height of 40 meters, appears like a ‘zero’ (egg-shaped ring from top), but from lower and angular views, it appears like a, ‘infinity’ symbol. The whole idea is to symbolize the endlessness of Zagreb which carries its rich history but envisions infinite prospects for its present and future, and reflects the eternal spirit of Zagreb and its people. The observation tower complex is designed to enliven the ‘dead’ floodplain of Sava river in the heart of Zagreb and connect the people of North Zagreb to South Zagreb.

Rian Architects and Designers' proposal envisioned an infinity loop; a bold, simple, and innovative gesture reflecting the eternal spirit of Zagreb and its people.


--- (Jury's comment)


Zagreb, developed along the Sava river, has a rich history dating from the Roman period. Sava river divides the city into North and South parts, connected by some bridges. However, people lack the true experience of connection between the two parts of the city apart from the transportation connection. It needs an urban design and architectural proposal to create a sense of connection through the visual experience and common activities and events. The proposed site of the tower is the heart of Zagreb where Sava river changes its path creating a curved barrier between North and South. The shape of the tower takes the inspiration of this striking curved form of the river to reflect the flow of time from past to present to future. The tower as a hyperbolic paraboloid ring offers circular and vertical movements as a continuous staircase having an additional four sets of curved escalators. This continuous stair symbolizes the endless movement on the tower offering ‘infinite’ viewpoints to the visitors, allowing to look over the whole city, the old and new landmarks of the city, and reminding the rich history of the city and inspiring for the prospect of the future.  


Great flood in 1964 insisted Government to make a wide floodplain at both sides along the Sava river. There are no very frequent floods in Zagreb recently, and hence, the floodplain remains almost empty and people rarely use this wide and long open space. It is not properly integrated with the city and its people. This proposed tower complex is designed to activate the floodplain so that the visitors can be attracted here for outdoor activities and events. The tower complex will act as an urban anchor to bring the people from North and South of the city to the heart of the Zagreb and thus resonating an urban pulse to the old and new wings of the Zagreb.


The structure has only two supports that occupies a very minimum ground space. This minimum area of supports enables visitors to enjoy free movement under the structure. The whole structure is one large trussed ring which is supported on two concrete blocks (hidden under the podium) that carry loads of the whole ring. The trussed ring is covered with non-reflective steel cladding whose metal yet neutral color makes a harmony with the nature and the surroundings, and highlights the boldness of its simplicity, making it a unique landmark of Zargeb.

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