While winemaking has since staked a claim both north and south of the capital city of Santiago and its convenient market of 6 million inhabitants, the Maipo Valley was (and still mostly is) the home base for Chile's largest and most well-known wineries, many of which were founded in the late 1800s. French varietals were what the owners of these estates cultivated, with root stocks acquired during their travels—Cabernet Sauvignon, Sauvignon Blanc and Carmenère. The Maipo Valley is, very loosely, divided into three regions: the Alto Maipo, closest to the towering Andes mountains in the east; the central Maipo on the valley floor, some of which borders the Maipo River, and the coastal Maipo, where weather patterns are to a small degree influenced by the sea (although the Maipo technically has no coastline.) Mountains surround the valley on three sides. Such geography keeps the valley generally warm during the days but cool at night.