A Christie's employee poses with Marc Chagall's "Le Cheval Vert" (L) and Pierre Bonnard's "Terrasse a Vernon" at Christie's auction house in London February 4, 2011. Christie's estimats that the pieces are will fetch 1.8 million U.S. dollars and 6.4 million dollars respectively when they come to auction as part of their Impressionist and Modern Art sale in London on February 9. [Xinhua]