Bordeaux

 The wine regions of Bordeaux are the divided by the Gironde River into a Left Bank area which includes the Médoc and the subregions of St-Estèphe, Pauillac, St.-Julien, and Margaux and a Right Bank area which includes the subregions of Saint-Émilion, Pomerol, Bourg and Blaye. Additional wine regions include the area of Graves which is south east of the Médoc and includes the sub regions of Pessac-Léognan, Sauternes and Barsac. Across from the Graves, on the Right Bank, is the Entre-Deux-Mers area between the Garonne and Dordogne rivers.

is that the Left Bank is predominately Cabernet Sauvignon based with the Right Bank more Merlot based. The Graves area produced both red wine and white wine from the Sauvignon blanc and Sémillon grapes. The area of Sauternes and Barsac are more known for the botrytized dessert wines.

Adapted from Wikipedia.