UNESCO recognises the outstanding universal value of this World Heritage Site under these criteria:
Criterion (i): The Forth Bridge is a masterpiece of creative genius because of its distinctive industrial aesthetic, which is the result of a forthright, unadorned display of its massive, functional structural elements.
Criterion (iv): The Forth Bridge is an extraordinary and impressive milestone in the evolution of bridge design and construction during the period when railways came to dominate long-distance land travel, innovative in its concept, its use of mild steel, and its enormous scale.
“This railway bridge, crossing the Forth estuary in Scotland, had the world’s longest spans (541 m) when it opened in 1890. It remains one of the greatest cantilever trussed bridges and continues to carry passengers and freight. Its distinctive industrial aesthetic is the result of a forthright and unadorned display of its structural components. Innovative in style, materials and scale, the Forth Bridge marks an important milestone in bridge design and construction during the period when railways came to dominate long-distance land travel.”
This World Heritage property boundaries are defined by the contracts that were let for the construction of the masonry and steel elements of the Bridge. The World Heritage Site does not extend beyond the Forth Bridge itself because outstanding universal value could only be clearly demonstrated for this single structure. It is, however, contained at each end by Conservation Areas. Its immediate surroundings are therefore protected and managed through well-established designation and planning controls.
A key factor when considering the protection of World Heritage Sites is their setting. In the case of the Forth Bridge the potential impact on its outstanding universal value of developments around the Firth of Forth has been subject to rigorous study using computer-generated “viewshed” analysis and physical investigation of as many viewpoints as possible. Ten of these viewpoints have been selected for specific attention by planning authorities.