Since the turn of the millennium, the red table wines of Portugal's Douro region have been mostly on a one-way trajectory of quality: straight up. The recently released 2011 vintage from the Douro, the heartland of Portugal's red wine production, ranks as the best yet—and the culmination of years of hard work in vineyards and cellars by the region's visionary vintners. The vintage also benefited from fortuitously warm and dry harvest weather, after a long and mostly uneventful growing season. The 2011s are destined to cement the Douro's place as one of the world's great red wine terroirs. If you have never tasted these distinctive and powerful wines, now is the time. Wine Spectator's Kim Marcus explains.