This is the "A Musical Party in a Courtyard" painted by Pieter de Hooch. We see a young woman playing the violin, with her instrument resting on the table upright, like a cello. She's surrounded by fine details - a pearl necklace, long earrings, and an ornament in her hair. The man sitting next to her is smiling at her, while she looks down at her music with great concentration.
De Hooch has given hardly any architectural detail to the courtyard where they're sitting, but instead focused on the houses across the canal. These buildings are similar to those you'd find on Amsterdam's canals and one of them even bears a tablet with the date 1620. Between us and these houses is a pavement, balustrade, and canal.
What catches our eye, though, is the enigmatic figure in the archway. He's in silhouette, turning away from us as if watching something on the other side. This adds an air of mystery to the scene, leaving us wondering what he's doing there and where he might be going.
A Musical Party in a Courtyard 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.