Bordeaux, the iconic French wine region, is home to more Merlot and Cabernet Sauvignon than anywhere else on the planet.
Once owned by the British after the marriage of Duchess Eleanor of Aquitaine to King Henry II, Bordeaux rose to prominence on the back of it's Claret, exported and gaining notoriety all around globe thanks to the long reaches of the British Empire, and the fact that at that time, it was not subject to taxing.
The climate in Bordeaux is maritime, for despite being situated in the southwest of France, it is not subject to Mediterranean heat. Generally speaking, Bordeaux can be split into three distinct sections, Left Bank, Right Bank and Entre-Deux-Mers.
The Left Bank, called that due to itself positioning alongside the Gironde River, stretches from Médoc to Graves, it's soils are largely gravel and it's reds based on Cabernet Sauvignon.
The soils of the Right Bank tend to be more limestone, known to give it's reds, generally based on Merlot and Cabernet Franc, more silky tannins and high acidity. This attributes are noticeable in the wines from Libournais, Bourg and Blaye. Popular areas located on Bordeaux's right bank are Pomerol and Saint-Émilion.
Entre-Deux-Mers contains a complexity in soil type due to it's proximity to both the Garonne and Dordogne River, generally speaking it is a combination of the Left Bank and Right Bank and as such, you're likely to see red blends both Merlot and Cabernet Sauvignon based.