The German artist George Grosz, best known for his vitriolic social criticism, inserted an enraged self-portrait in the lower right-hand corner of this work, painted during the last months of the First World War. Originally shown a century ago in the artist’s solo exhibition at the Galerie Neue Kunst in Munich, the painting has been in a private collection since 1970 and was last exhibited at the Haus der Kunst in 1999. It makes its auction debut at Christie’s and is “arguably the best and most complex” of the artist’s surviving cityscapes held in private hands, according to Olivier Camu, the auction house’s deputy chairman of Impressionist and Modern Art. George Grosz's Gefährliche Straße (1918). Impressionist and Modern Art, Christie’s, London, 5 February. Estimate: £4.5m-£6.5m. Courtesy of Christie's