A woman photographs St Paul's Cathedral from the top of an installation entitled 'Endless Stair' designed by de Rijke Marsh Morgan Architects (dRMM) near the Tate Modern gallery in central London on September 13, 2013. Inspired by MC Escher's famous surreal drawings of never-ending staircases, it was created to mark the launch of the London Design Festival which runs from 14th - 22nd September. AFP PHOTO / CARL COURT -- RESTRICTED TO EDITORIAL USE, MANDATORY MENTION OF THE ARTIST UPON PUBLICATION, TO ILLUSTRATE THE EVENT AS SPECIFIED IN THE CAPTION (Photo credit should read CARL COURT/AFP/Getty Images)