This is "An Architectural Caprice" painted in the Italian north by Francesco Guardi. The staircase here is based on one found in the courtyard of the Doge's Palace in Venice, but with some changes - some statues have been left out and the size of the square has been reduced to create a more intimate space.
As we look at the painting, we see a sunlit courtyard beyond the dark shadows of the arcade. The illuminated figures crossing it catch our eye, while more figures, suggested by dabs of paint, lead us up the stairs. High above, two people drape a blue cloth over the pale stone.
Guardi has shown only part of the right-hand arch, placed at an unusual angle to the dark row of arches on the right and those across the square. This creates the sense that the scene continues beyond the picture. The buildings are made up of continuous sweeps of golden brown tones, with architectural details hinted at in dark lines.
This painting would have been very popular with tourists as it evoked the atmosphere of Venice. In fact, Guardi's paintings from this period were known for being 'picture postcard' views - small and affordable souvenirs that could be easily transported by travellers during their Grand Tour of Europe.
An Architectural Caprice hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.