Trafalgar Square is a large public square in central London. The name of the square commemorates the British victory in the Battle of Trafalgar in 1805 over France. At its center is Nelson's Column, which commemorates Admiral Lord Nelson who died during that battle.
Sherlock Holmes: A Game of Shadows[]
This square is located sufficiently far from 221B Baker Street that Sherlock felt he did not need to work about Moriarty's spies anymore when he passed here when traveling to Watson's bachelor party.
Elementary[]
In "Step Nine", Sherlock reaches out to Langadale Pike to learn of the name of people who bought 3-D printers at this location.