Trafalgar Square is a major public square in the City of Westminster, Central London, and one of the city's most famous landmarks. Built in the 1830s, the square is named in commemoration of the Battle of Trafalgar in 1805, a British naval victory during the Napoleonic Wars.

Landmarks and features:
* Nelson's Column: This monument, built between 1839 and 1843, honors Admiral Lord Nelson, the British commander at the Battle of Trafalgar. The 185-foot (56 m) tall column is topped by a statue of Nelson and is guarded at its base by four large bronze lions.
* The Fourth Plinth: The square has four plinths. Three hold statues of notable figures, while the northwest plinth (the "Fourth Plinth") was left empty for years due to a lack of funds. Since 1999, it has been used to display a rolling program of contemporary art commissions.
* National Gallery: The square is dominated on its north side by the National Gallery, an art museum founded in 1824 and completed in 1838. It holds an extensive collection of paintings, including works by artists such as Leonardo da Vinci and Van Gogh.
* St Martin-in-the-Fields: This Anglican church, with its distinctive steeple, stands on the northeast corner of the square. Its popular Café in the Crypt is located in the church's basement.
* Fountains: The two prominent fountains in the square were designed by Sir Edwin Lutyens and installed between 1937 and 1939.

Traditions and public life:
* Protests and gatherings: Trafalgar Square has long been a key location for political demonstrations and community gatherings. Notable events have included suffragette rallies, anti-war protests, and the annual Women's March.
* Christmas tree: Since 1947, the city of Oslo, Norway, has donated a large Christmas tree to London as a token of gratitude for British support during the Second World War. The annual lighting ceremony is a popular public event.
* New Year's Eve: The square is a traditional center for New Year's Eve celebrations in London.