Called the "City of Bridges," Porto is Portugal's second largest city and the gateway to the Douro River Valley. Porto is also one of Portugal's oldest cities, having Roman roots dating from about 300 BCE. The city's location on the Douro River close to the Atlantic Ocean made it a natural settlement area. It became an important boat-building city and served as the launching point for Prince Henry the Navigator's 15th century explorations of Africa, which ushered in the "Age of Discovery" and boosted Porto's growth as a trading port. The 17th century saw wine give the city an economic lift that led to the construction of the beautiful Baroque buildings that UNESCO designated a World Heritage Site in 1996. Today, Porto is famous for its port wine, baroque architecture, and quintessential blue tiles called azulejos. It retains its Old World charm, with its hilly terrain, pastel houses, and terra-cotta roofs, but it also has developed a reputation as a cultural magnet, being named a cultural capital of Europe in 2001 and attracting tourists who have discovered its many delights. Whether strolling along pedestrian streets, touring historic churches, or sipping wine at a riverside cafe, Porto offers options for everyone.