The small sub-region of Pomerol is situated north-east of the industrious city of Libourne. Pomerol's soils are predominately iron-rich clay with a smattering of gravel that produce wines with extraordinary power and depth. As a result of this clay-dominance, it has the highest percentage of Merlot planted in all of Bordeaux. Certain châteaux are produced exclusively from this grape, but most incorporate smaller quantities of Cabernet Sauvignon and Cabernet Franc as well. Despite its hefty (if not exclusive) proportion of Merlot, many people think of wines from this region as separate entities. As one wine aficionado stated recently, "It's not Merlot. It's Pomerol." Despite the region's small size, Pomerol contains some of the world's most sought after (and expensive) wines including Pétrus, Le Pin, Lafleur, l'Evangile and Vieux Château Certan. Unlike other Bordelais subregions, there is no system of classification. The châteaux are traded on reputation alone.