Trafalgar Day is a celebration of the victory of the Royal Navy under the command of Vice Admiral Horatio Nelson (Horatio Nelson, 1758–1805) over the combined fleets of France and Spain in the Battle of Trafalgar, the largest naval battle of the 19th century during the Napoleonic Wars (1800- 1815).
On October 21, 1805, the 47-year-old Nelson's fleet gave a decisive rebuff to the French-Spanish fleet, preventing the French invasion of Britain. Lord Nelson himself was killed in battle.
In honor of the victory at Trafalgar, William IV Square in the very center of London was renamed Trafalgar Square. By 1843, a granite column 46 meters high with a five-meter figure of Nelson at the top was built there.