California as a wine producing region has grown in size and importance considerably over the past couple of centuries, and today is the proud producer of more than ninety percent of the United States' wines. Indeed, if California was a country, it would be the fourth largest producer of wine in the world, with a vast range of vineyards covering almost half a million acres. The secret to California's success as a wine region has a lot to do with the high quality of its soils, and the fact that it has an extensive Pacific coastline which perfectly tempers the blazing sunshine it experiences all year round. The winds coming off the ocean cool the vines, and the natural valleys and mountainsides which make up most of the state's wine regions make for ideal areas in which to cultivate a variety of high quality grapes. When it comes to New World wines, and especially wines from the United States of America, Napa Valley is something of a standard bearer. Over its relatively short history, it has managed to transform itself from being a fairly insignificant region, to becoming one of the most important and highly regarding wine locations on earth. With an ideal climate for viticulture, blazing sunshine and a low level of rainfall, this valley is shielded on many sides by mountain ranges which help it maintain a consistent level of heat, light and moisture throughout the year. Today, Napa Valley is a home of innovation and quality, with dozens of grape varietals thriving in the fertile soils. However, the main varietals grown there have always been Cabernet Sauvignon, Chardonnay, Pinot Noir, Merlot and Zinfandel, and the wines they produce are constantly lauded by critics and competitions across the globe.