Yes, it’s expensive and you have to reserve a tour and tasting in advance, but this 217-acre sparkling wine estate, a landmark once frequented by Robert Louis Stevenson and the second-oldest property in Napa Valley, is one of the valley’s all-time best places to explore. For decades Schramsberg’s delicious sparkling wine has been the label U.S. Presidents serve when toasting dignitaries from around the globe. The mystique begins the minute you park in the lot and wander toward the greeting area, where lush, overgrown foliage surrounds picture-perfect ponds (plan time for plenty of selfies!). The sparkling wine caves, which wind 2 miles (reputedly the longest in North America), were partly hand-carved by Chinese laborers in the 1800s; with dangling cobwebs and seemingly endless passageways, the caves have an authentic Tom Sawyer ambience, and you can’t help but feel you’re on an adventure. The comprehensive tour includes a stop in a formal tasting room, where you’ll sample surprisingly varied selections of their high-end bubbly. Davies Vineyards, at 1210 Grayson Ave. in St. Helena.