Originally the building’s design was criticised. It was only one room deep and very cramped. King William IV called it “a nasty pokey little hole”. Since then there have been many alterations and additions with large architectural spaces arranged on a Greek-Cross plan.
Modernised over the years, the building's façade onto Trafalgar Square, the Victorian interior decoration and other classical details remain unchanged.
The collection of over 2000 paintings contains some of the world’s greatest works of art, including Vermeer’s “A Young Woman Standing at a Virginal”, “The Arnolfini Portrait” by Jan van Eyck, and Turner’s “The Fighting Temeraire” as well as masterpieces by Titian, Michelangelo, Leonardo da Vinci, Constable ,and van Gogh.