Welcome to Porto, the second city of Portugal. Known on some English-language maps as Oporto (the Portuguese call it 'o Porto' in conversation, meaning simply 'the Port'), this attractive, ancient city is most famous today not for the port itself but for what's shipped out of it.

Follow this river, the Douro, east out of the city and you'll soon enter a valley flanked by vineyard-covered embankments. This long, narrow wine country is where world-renowned port wine is produced: A smooth, typically red wine fortified with a grape brandy to halt fermentation, resulting in a sweeter beverage. Douro Valley vintners send their product downriver to Porto—from there, it ships off to dessert tables worldwide. To be called port, the wine must come from the Douro Valley—a stipulation dating from the 1750s—making the area one of the world's oldest protected wine regions.