Tour begins: 5:30 PM, Palacio de los Duques Gran Meliá. Welcome to Madrid! A transfer is included from Madrid Airport to Palacio de los Duques Gran Meliá, in the Madrid de los Austrias, next to the Royal Palace and the Almudena. Join us for a welcome reception and dinner.

You have a choice of sightseeing. Explore a neighborhood market where you can get a taste of tapas, artisan foods, and delicacies from all over Spain; your visit ends sweetly with churros and hot chocolate! Or go on a bicycle excursion through the city's largest park, Casa de Campo; once a royal hunting estate, the 4,000-acre park is still inhabited by deer and rabbits; it also features an amusement park and the Madrid Zoo. Take a guided tour of the Royal Palace, a stunning baroque complex with 3,400 rooms and a wealth of artwork, antiques, porcelain, silver, and historical artifacts; or peruse the masterpieces at the Museo del Prado – one of the most famous art museums on Earth – on a guided visit with a local expert. The rest of the afternoon and evening are yours to spend as you wish in Spain's storied capital city.

Drive to beautiful Salamanca, a center of learning since medieval times, where a walking tour through the Old City reveals opulent Baroque, Moorish, and Gothic architecture, Romanesque cathedrals steeped in glorious frescoes, and the enchanting courtyards of the University of Salamanca, chartered in 1218, where Cervantes went to school; the area is nicknamed "La Dorada" (Golden City) for the warm glow that seems to emanate from its sandstone buildings. Then head to the riverside village of Barca d'Alva – a quiet town on the Portuguese border surrounded by placid, reflecting waters, close to the unspoiled wilderness of Arribes del Douro Natural Park – where your riverboat awaits; the hills are rich with olive groves, vineyards, and almond orchards that bloom with white flowers in spring. Embark, settle in, and join us tonight for a welcome reception and dinner.

Visit Castelo Rodrigo, a medieval hilltop village with a turbulent history, where battles were once fought against Moors and Spanish rule; the empty ruins of its 13th century palace still stand guard over the walled town with its churches, Manueline pillory, cistern, and panoramic vistas. Return to the ship for lunch and sail to Pocinho; from there you'll set off on a rock-art safari in Vale do Côa Archaelogical Park, to see stunning examples of rock-art from the valley's Paleolithic era, 20,000 years ago. Unlike cave art found in other parts of Europe, the thousands of petroglyphs in the Côa region were created in the open air by the valley's earliest inhabitants; the site is accessible only in 4x4 vehicles.

Spend the morning cruising the Douro River Valley where rugged conical mountains and shale hills carved by concentric vineyard terraces tell of a winemaking history thousands of years old. Since the 18th century, when Britain discovered that Portugal's fortified wine could travel long sea journeys without spoiling, the Douro Valley has been the premier port supplier to the world, and the oldest demarcated wine region. Sail the dramatic Valeira Gorge, where the river ran wild and treacherous before it was tamed by dams; in earlier centuries, small wooden boats called rabelos, heaped with barrels of wine, would negotiate rocks here and shoot the rapids on their way downriver. Arrive in the idyllic, tranquil village of Pinhão, nestled at a riverbend in the valley's premier Cima Corgo region, home to prestigious port-wine estates; a walking tour of Pinhão includes the enchanting railroad station, built in the 1930s and covered in azulejos, pictorial blue tiles that illustrate the region's winemaking heritage.

Explore the picturesque area around Pinhao by kayaking along the slow, easy river, or drive to a nearby hilltop village for spectacular views over the valley, and hike back down; on the way, you'll be able to appreciate up close the workmanship of the steep terraced vineyards. Lunch aboard ship and sail to historic Peso da Régua in the Baixo Corgo region of the valley. After docking, enjoy a visit to the Museu do Douro in Régua. Housed in a renovated 18th-century building, the museum features multimedia exhibits that tell the history of viniculture in the Douro River Valley; also on exhibit is a restored rabelo, one of the slender wooden vessels that used to ply the river in great numbers, carrying wine to Porto and the sea. Tonight, dinner is aboard your ship.

Before there was a railroad, Peso da Régua was an important shipping hub where rabelos took on cargoes of port from the local wine estates. Roads from here reach in many directions, offering you a choice of sightseeing possibilities. Take a bicycle tour through Vinho Verde country. Light and effervescent Vinho Verde is not actually green wine; depending on whom you ask, the name refers to its youth or the region it's from: a fertile, temperate land of vineyard-clad mountains and lush green valleys rich with scenic bicycle trails. Or drive to the medieval town of Guimaraes for a walking tour; known as the Cradle City, the kingdom of Portugal was born here after a momentous battle in 1128. The city center is a panorama of architectural treasures, including the ruined Castle of Guimaraes, with its tempestuous history and sweeping views, the opulent Dukes of Braganza Palace, and the 13th-century Sao Miguel do Castelo Church. Return to your ship this afternoon for lunch.

Wind through the Baixo Corgo region of the Douro Valley, where quintas and terraced vineyards rise on both sides of the river, showing their age; the oldest terraces are buttressed by stone walls, others have dirt walls; the valley's heritage is written in the stone walls, centuries old, but as they crumble they are too expensive to replace. Arrive in Porto by the sea in late afternoon, and dine aboard ship; after dinner, enjoy a performance by a local "Tuna" ensemble – a youthful academic string band that plays festive traditional music.  

Rising on staggered hills along the river, colorful Porto beckons you to its labyrinthine streets and stairways, medieval alleys, baroque churches, fountains, and bell-towers, beaux-arts buildings, and bohemian neighborhoods. It's hard to take a bad picture in Porto, where houses are clad in painted tiles, street art is everywhere, and beguiling, eclectic architecture is around every corner. Ride a three-wheeled taxi on a tour of iconic sights, including the Clerigos Belltower, a soaring baroque landmark, and 12th-century Porto Cathedral standing fortress-like on a hilltop overlooking the city; walk across the scenic Dom Luis I Bridge that spans the river and soak up the fabulous views; the bridge links Porto to the city of Vila Nova de Gaia, and you'll ride a cable car down to the Gaia waterfront. Or take a cycling tour along Porto's colorful riverfront, starting in the picturesque and lively Ribeira neighborhood, a UNESCO World Heritage site, and ending where the river meets the Atlantic. Lunch on the riverboat, then enjoy free time to explore on your own. Join us this evening back aboard ship for a farewell dinner.

Tour ends: Porto. Fly home anytime. Transfers are included from the riverboat to Porto Francisco Sa Carneiro Airport or Porto train station.  Allow at least three hours for flight check in.