On the occasion of World Sight Day, a giant yellow banner bearing three black spots to symbolize blindness was unveiled at Vienna.
The 13-by-16-meter (42.5-by-52.5-foot) banner will adorn a facade of the Gothic structure until Monday to raise awareness about blindness, especially in poor regions, where it can often be reversed with a simple and cheap operation.
The giant sign was made with some 3,600 smaller blind symbols, decorated by individuals, who used the black dots to make puppy faces or portray children playing football.
Local celebrities, including ski stars, actors and politicians also took part in the campaign, sponsored by the Austrian organisation "Licht fuer die Welt" (Light for the World).
In parts of the developing world, blindness is often inevitably linked to poverty and social exclusion.
A simple operation to restore sight can cost however as little as 30 euros ($41), according to Licht fuer die Welt.