This is a small but perfectly formed exhibition that runs at Tate Modern till next July. You can get a real sense of it in about 20 minutes, although it deserves a much longer and closer look. But if you’re in a hurry to see the other more famous displays on show on the South Bank, the first two rooms alone capture its essence. Start with Paul Klee’s wondrous watercolour Comedy, move on to George Grosz’s fabulously sleazy self-portrait, revel in the colours of Marc Chagall’s Green Donkey and then pop into the next room to marvel at Otto Dix’s gruesomely lowlife etchings – particularly The Butchers – and his brilliantly bloody watercolour Lust Murder. These pictures will tell you all you need to know about the national nightmare that engulfed Germany in the disastrous aftermath of the First World War.