Just 50 or so miles north of San Francisco, the Opus One estate stands as a partnership between Robert Mondavi and Baron Philippe de Rothschild. The stately winery, which was completed in 1991, incorporates classic architectural themes, paying homage to both Greek and Roman styles. Among the stalwart varietals is their Bourdeaux-caliber Cabernet Sauvignon, 1985 vintage of which was the first Californian wine to reach European shelves. After touring the facility, guests may taste the current vintages in the exclusive Partners' Room. Winery visits are by appointment only.