IAHM-COL wrote:... a pair of astonishingly beautiful bridges.
The Forth road and rail bridges, over the Firth of Forth. The rail bridge is a Victorian construction in iron and used to be famed for the task of painting, which took ten years by hand. By the time the painters had got from one end to the other, the start needed painting again, and it became a metaphor for a never ending task -- "like painting the Forth rail bridge".
Fortunately now they have some better paint:
http://www.bbc.co.uk/news/uk-scotland-16137688