The Musée d'Orsay is the world's finest collection of Impressionist and Post-Impressionist art, housed in a spectacularly converted 1900 railway station. Victor Laloux's Beaux-Arts iron-and-glass hall, with its giant clocks and ornate plasterwork, is as much an attraction as the paintings. The station closed in 1939 and the building spent decades awaiting demolition before reopening as a museum in 1986.
The collection runs from 1848 to 1914 and includes major works by Monet, Renoir, Degas, Cézanne, Van Gogh, Gauguin, and Seurat. The top floor is the place to start — the Impressionist rooms are up here, and the crowds thin as you descend. Don't miss Van Gogh's bedroom paintings, Monet's series works, and the enormous Courbet canvases in the ground-floor nave.
Thursday late opening is particularly pleasant: the crowds are lighter and the building glows golden in the evening light. Book tickets online; the queues here can rival the Louvre on busy days.