Impressionism was an art movement that began in 19th century France with artists like Monet, Pissarro, Degas, Sisley, Morisot, and Renoir. They captured scenes as quick glimpses using visible brush strokes, ordinary subjects, open compositions, and emphasis on light and unusual angles. Some key works include Monet's Water Lily Pond and Impression, Sunrise, Degas' Ballet Dancers, and Renoir's Boating on the Seine.