The expansive and varied Maipo Valley is nestled between two mountain ranges, the Andes and the Coastal Mountains, and Chile’s capital city, Santiago, sits in the middle. Due to the easy access to the surrounding agricultural areas, it comes as no surprise that many of the country’s best-known and most traditional wineries were established in close proximity to the city. In the 19th century, when many wealthy industrial families planted vineyards near their country homes to the east and southeast of the capital, surely they never dreamed that the city would grow to engulf them. But today the city of 6,000,000 people continues to stretch out into the surrounding areas. Winemaking in the Maipo Valley today ranges from tiny boutique efforts to large-scale multi-million liter production centers, from nascent dreams to time-honored traditions, from industrial-scale to biodynamic—and everything in between. The cause is not lost on foreign investors either. Winery architecture is equally diverse and includes everything from treasured national monuments to prize-winning ultra-modern designs. Although Chile’s appellations of origin are defined from north to south, winemakers now generally agree that conditions vary much more widely from east to west, as the Maipo Valley clearly illustrates. Winemakers unofficially divide the valley into three distinct sectors: Alto Maipo, closest to the Andes; Central Maipo, along the valley floor; and Pacific Maipo in the sector closest to the Pacific Ocean. All three enjoy a winemaker’s ideal Mediterranean climate with hot, dry summers and cool rainy winters, but vary with respect to the degree of influence received by the mountains or the sea. At more than 650 meters (2,133 ft) above sea level, the Alto Maipo sector (sometimes referred to as the Andean or Upper Maipo) rises ever higher into the foothills southeast of Santiago and is strongly influenced by the mountains. Vast differences between daytime and nighttime temperatures encourage complex, richly colored wines and firmly structured tannins that give rise to a number of Chile’s ultra-premium wines. To the south and southeast of Santiago, Central (or Middle) Maipo ranges from 550 to 650 meters (1,800–2,139 feet) above sea level, while the easternmost Pacific (or Lower) Maipo sector nearest the coast comprises areas below 550 meters (1,800 ft) a.s.l. These areas tend to have warmer temperatures and more fertile soils, giving rise to softer, fruitier wines. Many winemakers blend wines from different Maipo vineyards to take advantage of the diverse qualities available in the three distinct areas.