Shortly before the Duero River crosses into Portugal (and has its name changed to the Douro River), it weaves itself through the ancient town of Zamora. Travelers who appreciate history or architecture should visit the walled, medieval portion of the city or tour any of the dozen Romanesque churches. No other city in Europe can boast more of that style.

Travel is arduous but exhilarating when you reach the middle section of the Douro Valley near Pinhao, Portugal. This section is known as the Cima Corgo. Here, the steep contours of the Douro's bank are packed with terraced vineyards that supply the best grapes for Port production. Port vineyards are rated on a declining quality scale from A to F, depending on a list of natural and man-made variables. Vineyard location, aspect, vine density, gradient and soil composition are all part of the matrix. The better composite scores receive higher letter grades and that warrants higher prices for that vineyard's grapes. There are six main grapes (of the 48 permitted) widely considered to be the best for Port production. Of these six, Touriga Nacional and Tinta Roriz (Tempranillo) command the most respect.

Most of the big names in the Port trade have quintas, or winemaking estates, in the Upper Douro near Pinhao. Traditionally, the wines were fermented and fortified at the quinta, transferred to a 550 liter barrel, and then shipped down the Douro on barges called rabelos. The barrels of Port, called pipes, are off-loaded just a few kilometers from the Atlantic Ocean at Vila Nova de Gaia. This picturesque village sits directly across the river from Oporto, the city that lends its name to the wine. Vila Nova de Gaia's narrow streets are lined with the aging facilities of all the famous producers of Port. Shippers like Graham's, Dow's, Warre's and Fonseca all have lodges in Vila Nova De Gaia where they age, blend and bottle some of their fortified wines.

Many of the Port lodges are open to the public for tastings, tours, or retail sales. While you're there, treat yourself to some of the world's great fortified wine in the city that raised it. Take a moment to reflect on the hundreds of miles you've traversed, the elements of natural splendor and ancient culture you've seen and heard, the nostalgic aromas of Iberian regional cuisine, and of course, the specific sense of place in the diverse wines you've tasted. Revel in that as you sit on the bank of the mighty Douro River and savor the last sip of a 30-year-old Tawny Port in the golden afternoon sun.

Do you really think you would get all that from a train window?