NELSON'S COLUMN is a monument in Trafalgar Square in Central London built to commemorate Admiral Horatio Nelson, who died at the Battle of Trafalgar in 1805. The monument was constructed between 1840 and 1843 to a design by William Railton at a cost of £47,000. It is a column of the Corinthian order built from Dartmoor granite. The Craigleith sandstone statue of Nelson is by E.H.Baily and the four bronze lions on the base, added in 1867, were designed by Sir Edwin Landseer.
The pedestal is decorated with four bronze relief panels, each 18 feet (5.5m) square cast from captured French guns. They depict the Battle of Cape St Vincent, the Battle of the Nile, the Battle of Copenhagen and the Death of Nelson at Trafalgar. The sculptors were Musgrave Watson William F, Woodington, John Ternouth and John Edward Carew respectively.
In February, 1838 a group of 121 peers, members of Parliament and other gentry formed a committee to raise a monument to Lord Nelson, funded by public subscription, and the Government agreed to provide a site in Trafalgar Square, in front of the newly completed National Gallery. A competition was held for designs with an estimated budget of between £20,000 and £30,000. The deadline for submissions was 31 January, 1839
The winning entry. chosen by the sub-committee headed by the Duke of Wellington was a design by William Railton. The second prize was won by Edward Hodges Baily who suggested an obelisk surrounded by sculptures. Criticism of the organisation of the competition caused it to be re-run. Railton submitted a slightly revised design and was once again declared the winner, with the stipulation that the statue of Nelson should be made by E.H.Baily.
In 1844 the Nelson Memorial Committee ran out of money, having only raised £20.485 in public subscriptions, and the Government, in the form of the Office of Woods and Forests took over the project.
The column also had a symbolic importance to Adolf Hitler. If Hitler's plan to invade Britain, Operation Sea Lion, had been successful, he planted to move the statue to Berlin.
The column was refurbished in 2006, at which time it was scaffolded from top to bottom for access. Steam cleaning was used together with gentle abrasives to minimise any harmful impact on the bronze and stonework. £420,000 cost was covered by Zurich Financal Services, which advertised on the scaffolding for the duration of the work. Before restoration began, laser surveys were taken during which it was found that the column was significantly shorter than the usually quoted 185 feet (56.4m). In fact it measures 169 feet (51.5) from the bottom of the first step to the tip of the admiral's hat.
There is much more on Wikipedia with regard to how the statue etc was built if you should wish to learn even more than I have included here.