On the brink of the Depression in 1929, Georgia O'Keeffe - America's first great modernist painter - headed west. In the bright light of the New Mexico desert, she forged an independent life and found the solitude she needed for her truly original art. The photographs taken of her by her older lover scandalised the public. Her flower forms were seen as a shocking and vibrant display of femininity, her bones and skulls as surreal and disturbing. Now, 30 years after her death, to coincide with a major Tate Modern show, imagine... tells the story of Georgia O'Keeffe, one of the most inspiring artists ever.