The Bilbao Fine Arts Museum held a ceremony to celebrate the start of construction on 17 November. The expansion and remodelling project will restore the existing 20th century building, while creating a new public atrium space and contemporary art galleries in a floating pavilion. The design reorients the museum towards the city by creating a new pedestrian path across the museum from north to south. This path connects the original 1945 building, 1970s extension and a new visitor’s centre, while making the building more permeable at street level. The project is a celebration of the important role that culture can play in the civic life of a city.The guiding principle behind the project is to make the 1945 building the primary protagonist by restoring its original entrance and its logical internal sequence of spaces. The ground floor is on a single accessible plane allowing visitors to orient themselves easily. The revitalisation turns Plaza Arriaga into the new heart along the museum’s spine, with light streaming in from the rooflight piercing through the new gallery spaces above.The new extension is a unique structure that rests respectfully across the existing museum equipping it with 2,300 square-metres of new gallery spaces. The top floor contains a flexible, column-free, exhibition area which can be configured for a large range of displays, with all the service spaces neatly contained within two technical walls. Natural light filters through a panoramic window offering expansive views over the adjacent park, with north lights that can be moderated to suit the displays.The lower floor of the new extension offers space for educational programmes and workshops, offices and service areas. The new addition is characterised by a modelled façade with a viewing terrace to enhance its slenderness and host sculpture exhibitions. The use of cross ventilation, natural light as well as high thermal mass, solar energy and rainwater collection, reduce the environmental impact of the building. The new extension will be made using low carbon steel and features a roof which harnesses energy.The project also includes a series of interventions to improve the existing galleries and back of house spaces, to enhance the museum’s operations. The museum’s area will increase by 50 percent and 70 percent of the existing building will be upgraded – in essence, the design combines the best of old and new. The courtyard becomes a public gathering space, with new spacious galleries and viewing terraces hovering overhead.The Bilbao Fine Arts Museum will be the practice’s second project in the city, following Bilbao Metro, which was completed in 1995.