THE ILIRIJA CITADEL IN LJUBLJANA

A DIVERSE SPORTS CITY IN THE URBAN CITY CENTRE
In spring 2025, Ljubljana opened its Ilirija Sports City – a project that took a quarter of a century to complete: After almost 100 years, a historic outdoor swimming pool has been transformed into a new part of the city, an ‘urban citadel’ with a strategically dominant location, bordered by busy transport routes and with its own identity – created for the well-being of the population, who can not only enjoy a wide range of sports there, but also hold festivals, presentations and cultural events.
1. HISTORY
• 1929: Interwar period – with the Ilirija outdoor swimming pool built by Stanko Bloudek in 1929, Ljubljana gained a sporting landmark in the north-eastern part of Tivoli Park; nestled in an area that was used for a variety of purposes at the time, it was also a meeting place for famous architects such as Maks Fabiani (Jakopič Pavilion 1923–1962), Jože Plečnik (Jakopič Promenade, 1920s/1930s), and equipped with sports facilities, smaller grandstands, an ensemble of temporary halls and exhibition buildings for cultural and commercial events.
• 1942: Due to the relocation of the railway, the Baroque Latterman Avenue loses its function as the main access point to Tivoli Park. Ilirija was cut off from the park again.
• 1945: Tivoli Park regained its character as a purely green space.
• 1991: With the founding of the Republic of Slovenia, the question of modern sports infrastructure came into focus. The outdoor swimming pool was dilapidated and renovation seemed uneconomical.
• 1995: The city of Ljubljana decides to build an Olympic-standard 50-metre swimming centre on the site of the dilapidated pool – a conscious decision in favour of the central location.
• 2000/01: Slovenia's first international architecture competition, won by Lorenzateliers (CEO Peter Lorenz, Vienna/Innsbruck). The mayor is Viktorija Potočnik, followed by the development of a PPP model with many variants.
• 2007: The new mayor, Zoran Janković, decides to implement the project himself, without commercial and retail space and with a reduced space allocation plan.
• 2011: The Bloudek building is listed – a turning point in the planning process.
• 2012: The new development plan becomes legally valid.
• 2018: General planners Elea iC and Lorenzateliers ZT GmbH are officially commissioned with the implementation.
• 2021–2025: Construction period, general contractor Makro 5, opening in March 2025
The city council's decision in 1995 to choose the existing location is now proving to be very forward-looking for a climate-friendly city: less traffic, easy accessibility by public transport, by bicycle/on foot, energy-neutral concept, lower operating costs through multiple use, attractive urbanity.
2. URBAN CONCEPT
The design was always intended as an urban concept: how can this remaining plot of land, an isolated island between busy traffic routes, be reintegrated into the city? A renaissance of the park's historic, strong connections with the city.
• The winning project in 2000/01 envisaged land art architecture: a large roof spanning the halls and pools, accessible to pedestrians, to expand the limited open spaces, and a large sliding roof to transform the hall into an outdoor swimming pool.
• The restored Latterman Avenue runs diagonally through the sports centre into Tivoli Park as a ramp under the tracks – a connection of great urban and symbolic significance.
• The new public square in front of the buildings becomes an urban link between the city and the park.
• The multiple use of halls for sports, culture, concerts and events reduces operating costs and makes the facility economical.
Over the years, programmes and framework conditions changed, PPP models were considered, monument protection requirements were integrated, fossil fuels were eliminated, etc. The urban development concept of the sports city in the centre has endured all these years.
3. ICON ROOF
• The diverse functions are located under a 12.000 m² roof, and the swimming hall itself is spanned by a light steel structure with a 54-metre span, the roof surface equipped with 4.000 m² of PV panels, executed in the wrong colour.
• Open transparency via glass facades, daylight, visual connections to the street, railway and park.
• Raw materials: exposed concrete, galvanised steel, colour dots in three shades of blue.
4. FUNCTIONS
• Public space, weather-protected
• Bloudek building: café, exhibition, museum, reception
• Indoor swimming pool: Olympic pool (50x25 m) , 25-metre training pool, children's pool, grandstand for 1.500 spectators
• Sports halls: Four multi-purpose halls for ball sports, gymnastics, martial arts and events
• Outdoor facilities: Athletics track, beach volleyball, basketball courts
• Infrastructure:
Underground car park with 1.000 parking spaces, new footpaths and cycle paths The Ilirija sports centre is a new urban building block and mobility hub.
5. SUSTAINABILITY
The centre meets the standard of a zero-energy building:
• Solar panels and geothermal heat pumps ensure energy self-sufficiency.
• Fossil fuels have been consistently excluded.
• The national eco-fund is providing substantial funding for the project.
6. CRITICAL DEBATE
Important public projects generate a striking commonality in our democracies – different ideas provoke criticism, and only the realisation and use of the project can prove its validity:
• Critics accused the project of being oversized and poorly located – the outdoor pool should be renovated.
• Proponents emphasised the urban added value and the importance for climate policy.
• Architectural critic Christian Kühn praised the spatial diversity as a ‘work of spatial art’ and defined Ilirija as a ‘city within a city’.
The project authors invite constructive discourse on the survival of European cities.
7. SOCIAL AND CULTURAL VALUE With its urban diversity, the Ilirija citadel sees itself as an urban stage:
• Use by schools, universities, clubs, the general public, tourists
• Spaces for concerts, cultural events and social occasions
• Sport and the public are brought together and focus on economically viable use
• Transparency and openness to the city reflect the development towards an open society
• Ljubljana is positioning itself with a future-oriented and confident approach alongside other European capitals.
The ILIRIJA model shows how sport, culture and urban development can intertwine: the result of decades of debate, changing political priorities and architectural perseverance – today a pilot project for a ‘sports city’ in the heart of the city centre – sustainable, diverse and open.
8. PROJECT DATA
• Client: City of Ljubljana
• Competition: 2000/2001, 1st prize Lorenzateliers
• General planner: ELEA
• Planning: 2001–2020
• Construction period: 2022–2025
• Covered area: 12,000 m²
• Opening: March 2025