[6] In 1806, a pair of tunnels, one for each direction, was proposed, and in 1818 James Anderson produced a design for a three-span suspension bridge close to the site of the present one.

[10][11] The promoters, however, were concerned about the ability to set foundations in the silty river bottom, as borings had gone as deep as 231 feet (70 m) into the mud without finding rock, but Bouch conducted experiments to demonstrate that it was possible for the silt to support considerable weight.

[12] In August 1865, Richard Hodgson, chairman of the NBR, proposed that the company invest £18,000 to try a different kind of foundation, as the weighted caissons had not been successful.

[12] The platform was launched on 14 June 1866 after some difficulty in getting it to move down the greased planks it rested on, and then moored in the harbour for six weeks pending completion.

[12] In September 1866, a committee of shareholders investigating rumours of financial difficulties found that accounts had been falsified, and the chairman and the entire board had resigned by November.

This design was examined and pronounced acceptable by W. H. Barlow and William Pole, both "eminent" civil engineers, and Parliament passed in August 1873 an act authorising its construction.

[20] Bouch's 1871 design for the Forth Bridge fell significantly short of this figure, as – on the advice of the Astronomer Royal – he had assumed a wind loading of only 10 lb/sq ft (49 kg/m2).

[21] This had been accepted by Barlow and Pole in their 1873 assessment of the design, though they qualified in their report that "[while] we raise no object to Mr. Bouch's system, we do not commit ourselves to an opinion that it is the best possible".

[30] In order to illustrate the use of tension and compression in the bridge, a demonstration in 1887 had the Japanese engineer Kaichi Watanabe supported between Fowler and Baker sitting in chairs.

[32] The bridge was the first major structure in Britain to be constructed of steel;[33] its French contemporary, the Eiffel Tower, was built of wrought iron.

[49] Reginald Middleton took an accurate survey to establish the exact position of the bridge and allow the permanent construction work to commence.

[25] The rocky shore was levelled to a height of 7 feet (2.1 m) above high water to make way for plant and materials, and huts and other facilities for workmen were set up further inland.

[25] Wooden huts and shops for the workmen were put up, as well as more substantial brick houses for the foremen and tenements for leading hands and gangers.

[25] Near the shore a sawmill and cement store were erected, and a substantial jetty around 2,100 feet (640 m) long was started early in 1883, and extended as necessary, and sidings were built to bring railway vehicles among the shops, and cranes set up to allow the loading and movement of material delivered by rail.

[25] In 1884 a compulsory purchase order was obtained for the island, as it was found that previously available area enclosed by the four piers of the bridge was insufficient for the storage of materials.

[52] Many materials, including granite from Aberdeen, Arbroath rubble, sand, timber, and sometimes coke and coal, could be taken straight to the centre where they were required.

[52] Steel was delivered by train and prepared at the yard at South Queensferry, painted with boiled linseed oil, and was then taken to where it was needed by barge.

[54][55] This process used a positive air pressure inside a sealed caisson to allow dry working conditions at depths of up to 89 feet (27 m).

[58] When the caissons had been launched and moored, they were extended upwards with a temporary portion in order to keep water out and allow the granite pier to be built when in place.

[66] The curved plates were then assembled on a mandrel, and holes drilled for rivets, before they were marked individually and moved to the correct location to be added to the structure.

Two trains, each consisting of three heavy locomotives and 50 wagons loaded with coal, totalling 1,880 tons in weight, were driven slowly from South Queensferry to the middle of the north cantilever, stopping frequently to measure the deflection of the bridge.

[29] A few days previously there had been a violent storm, producing the highest wind pressure recorded to date at Inchgarvie, and the deflection of the cantilevers had been less than 25 mm (1 in).

The bridge was opened on 4 March 1890 by the Duke of Rothesay, later King Edward VII, who drove home the last rivet, which was gold plated and suitably inscribed.

In all, 12 German Junkers Ju 88 bombers led by two reconnaissance Heinkel He 111s from Westerland on the island of Sylt, 460 miles (400 nmi; 740 km) away, reached the Scottish coast in four waves of three.

Two bodies were recovered from the Crail wreckage and after a full military funeral with firing party, were interred in Portobello cemetery, Edinburgh.

[108] All previous layers of paint were removed using copper slag fired at up to 200 miles per hour (320 km/h), exposing the steel and allowing repairs to be made.

[110] In a report produced by J. E. Jacobs, Grant Thornton and Faber Maunsell in 2007 which reviewed the alternative options for a second road crossing, it was stated that "Network Rail has estimated the [remaining] life of the bridge to be in excess of 100 years.

[114] Also in 2005, Channel 4 documentary Jump Britain showed Sébastien Foucan, a French freerunner, crawling along one of the highest points of the bridge without a harness.

"[120] The bridge is included in the video game Grand Theft Auto: San Andreas by Edinburgh-based developer Rockstar North.

[123][68] In 2016, a VisitScotland survey voted the Forth Bridge "Scotland's greatest man-made wonder", beating off competition from Stirling Castle, the Caledonian Canal, the Scott Monument, Bell Rock Lighthouse, and Melrose Abbey.