Port wine takes its name from Porto, though the grapes grow 100 kilometers upstream in the Douro Valley and the cellars that age the wine sit across the river in Vila Nova de Gaia. The British merchants who developed the trade in the 17th century found that adding brandy to the wine helped it survive the sea voyage to England; the fortification became the defining characteristic, producing a sweet, strong wine that became essential to British tables.

The lodges of Vila Nova de Gaia - Taylor's, Graham's, Sandeman, and dozens more - line the waterfront, their cellars cool and dark beneath the streets. Tours lead through barrel rooms where port ages for decades, the angel's share evaporating into air thick with wine scent. The tasting rooms offer vintages that cost more than meals; the bottles sold in shops offer the same experience for less. The port trade has declined from its peak but persists as heritage tourism, the cellars that stored wealth now storing memory.

The Dom Luis I Bridge is Porto's postcard image - a double-deck iron arch spanning the Douro gorge, pedestrians crossing the upper level while traffic takes the lower. Gustave Eiffel's company designed the nearby Maria Pia railway bridge in 1877; the Dom Luis, completed in 1886, was built by one of his former partners. The resemblance to the Eiffel Tower's ironwork is not coincidental.

Six bridges now cross the Douro in Porto, each representing different eras and engineering. The newest, the Infante D. Henrique Bridge, opened in 2003 with a concrete arch that contrasts with 19th-century iron. The bridges transformed Porto from a city divided by its river into a city connected by it, the Ribeira waterfront on the north bank linked to the wine cellars on the south. The views from the upper deck of the Dom Luis - the red roofs tumbling down to the water, the boats bobbing at their moorings - define what Porto offers: dramatic geography transformed into urban beauty.

The Ribeira - the riverfront quarter - is UNESCO World Heritage, its medieval streetscape preserved despite centuries of flooding and rebuilding. The houses stack up the hillside in layers of red tile and painted plaster, the laundry strung between windows, the cafes spilling onto the waterfront promenade. The quarter was poor for most of its history, its residents the fishermen and dockworkers who served the wine trade; gentrification arrived with tourism, raising prices without erasing character.

The rabelo boats that once carried wine barrels downriver now carry tourists, the flat-bottomed craft unchanged in design for centuries. The restaurants serve francesinha - Porto's contribution to the hangover cure, a sandwich of meat and cheese drenched in beer sauce - alongside grilled sardines and bacalhau. The Ribeira fills on summer evenings, the sound of fado drifting from bars, the lights of Vila Nova de Gaia reflecting on the dark water. The quarter offers what tourism brochures promise but Porto actually delivers.

Azulejos cover Porto - the blue and white ceramic tiles that decorate churches, stations, private homes, and seemingly every available surface. The Sao Bento railway station hall is perhaps the finest example, its walls covered with 20,000 tiles depicting Portuguese history, installed between 1905 and 1916 by artist Jorge Colaco. The Igreja do Carmo displays religious scenes on its exterior; the Igreja de Santo Ildefonso glows blue in afternoon light.

The azulejo tradition came from Moorish Spain but became distinctly Portuguese, the blue and white color scheme dominating from the 18th century onward. Porto adopted the tiles more enthusiastically than other cities, creating streetscapes where the ceramic surfaces catch and reflect light. The effect is cumulative - no single tile panel is remarkable, but the city itself becomes artwork. The tiles require maintenance that Porto has not always provided; restoration projects address the flaking and damage that decades of neglect created.

Porto's rivalry with Lisbon shapes its identity. The capital has government and tourism and international attention; Porto has industry and authenticity and pride. FC Porto competes with Lisbon's clubs; the University of Porto competes with the University of Lisbon; the businessmen of Porto consider themselves harder-working than the bureaucrats of the capital. The rivalry is not quite balanced - Lisbon is larger and wealthier - but it is real.

The city has reinvented itself for the 21st century, attracting tech companies and startups, transforming industrial buildings into cultural venues, marketing itself as the alternative to an increasingly touristed Lisbon. Porto works because it retained the industrial base that other Portuguese cities lost, because the wine trade kept international connections alive, because the spirit of the tripeiros - practical, resilient, stubborn - proved adaptable. The city that gave Portugal its name continues to define what Portugal means, even if the capital disagrees.