Christie's is the world's leading auction house - a great British institution that has evolved into a revered and dominant international brand. But little is known about Christie's beyond its saleroom walls. Now, for the first time, cameras have been given access to Christie's global empire and its auction houses across the world, from New York to Shanghai and Dubai to Hong Kong. As the auction house prepares for its 250th anniversary, the pressure is on to make this a bumper year. Will enough great art works come through Christie's gilded doors? Who is buying which pieces of art - and what can this tell us about the way the art world, and the world at large, is changing?