This is the "Bathers at La Grenouillère" by Claude Monet. Painted in 1869, it's one of several works Monet created at La Grenouillère, a popular resort on the river Seine just outside Paris.
Monet was painting what he saw without any attempt to tidy up the scene, capturing fleeting visual effects and impressions that changed moment to moment. You can see how quickly and directly he painted this - it's almost like a sketch, but one that's full of character.
Notice how Monet uses bold brushstrokes and strong colours to create a sense of energy and movement in the painting. He's not concerned with creating a realistic representation of La Grenouillère; instead, he's trying to convey his own experience of the place.
Monet was part of a new movement in art, one that would eventually be known as Impressionism. And paintings like this one show why - they're all about capturing the modern world and the way it looks and feels, rather than just copying what's already been done before.
Bathers at La Grenouillère 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.