In this fascinating fifth series we cover the huge range of art treasures which go under the hammer every year in London, New York and Paris. From Old Masters, through twentieth-century furniture to classic cars. Among the highlights are Monet's Water Lilies, sold for over £31 million; Guardi's view of Venice, knocked down for nearly £10 million and a traction engine, sold in Cambridgeshire for over £100,000.