The fourth bridge in our alphabetical Christmas countdown is a structure in Norway by artist Vebjørn Sand, which is based on a previously unrealised design by Leonardo da Vinci.
The Da Vinci Bridge, also known as the Leonardo Bridge and the Golden Horn Bridge, was designed in response to a sketch produced by the Italian polymath in 1502.
While the original scheme was proposed across the Golden Horn waterway in Istanbul, the structure was eventually built in Norway in 2001. It provides a pedestrian crossing over the E18 motorway at Nygårdskrysset, south of Oslo.
Its form is provided by four slender wooden ribbons – three structural arches and a gently curving deck.
"It is not one of your great bridges," wrote Jan Morris in the Wall Street Journal. "It is only a footbridge, in fact, going nowhere in particular but beloved of boys with bikes because of its steep inclines. It is, however, extremely beautiful."
"A sweeping structure of pine, teak and stainless steel, its path is supported by complex parabolic piers that give it a majesty far beyond its size."
Da Vinci's original sketch of the design was discovered in the national archives in Istanbul in 1952, accompanied by the letter he wrote to Sultan Bayezid II proposing it as the greatest single-span bridge of the ancient world.
This prompted Vebjørn Sand to embark on a project to realise a version of the bridge in as many places as possible, starting with his home country.
Working in collaboration with Selberg Arkitektkontor and Reinertsen Engineering, he scaled down the design from its original 240 metres to a more modest 109 metres.
The artist also replaced the stone arches proposed by Da Vinci with glue-laminated timber, making the bridge cheaper and more environmentally friendly. He describes it as "a re-imagining of Leonardo's eloquently flexible design".
A non-profit organisation has been established around the project to support the construction of more bridges based on the sketch.
In return for use of the design, the Leonardo Bridge Project charges three per cent of the final construction budget. No others have yet been revealed, although several temporary ice versions have been created.
In the spirit of an advent calendar, Dezeen will publish another bridge every day until Christmas. See all the ones revealed so far »
Images courtesy of Broer.