Amedeo Modigliani was high on hashish, wrecked by absinthe, and desperately poor when he painted this hymn to lust in 1917-18. Almost a century later, Nu couché is the second most expensive painting ever sold. On Monday night it went for $170.4m (£113m) at Christie’s in New York. Only Picasso, whose Women of Algiers set the $179m record for a painting sold at auction in May, is more expensive.