The Rapel Valley is a large Chilean production region that guarantees about a quarter of all the nation's wine. It creates a wide range of wine styles, ranging from everyday wines to excellences of absolute prestige. Viticulture is mainly based on the cultivation of red grape varieties, including Cabernet Sauvignon, Syrah and Carmenère, as well as the Malbec that has become famous in adjacent Mendoza, but there are also some productions of Chardonnay and Sauvignon Blanc. Surrounded on both sides by mountain ranges - the Andes to the east and the Coast Range to the west - the Rapel Valley is largely protected from the cold currents of the Pacific Ocean. It owes its name to the Rapel river of the same name, born from the confluence of the Tinguiririca and Cachapoal rivers, which trace the boundaries of two very different sub-regions: the Cachapoal Valley to the north and the Colchagua Valley to the south. In the Cachapoal Valley the best vineyards are located on the east side, to which the Andes provide beneficial protection for viticulture. In the Colchagua Valley, on the other hand, the best vineyards extend to the west, where the cold influences of the ocean contribute to the creation of more elegant and balanced wines. While the Cachapoal Valley is better known locally, the Colchagua Valley has made itself known internationally. The Rapel Valley does not cover a specific administrative area but is part of the wider O'Higgins region which takes its name from one of the most famous leaders of the War of Independence from Spain in the 19th century.