The Corridors: from Chicago to San Francisco by train - California Zephyr

Chicago rises along the southwestern shore of Lake Michigan, the third-largest city in the United States and the acknowledged birthplace of the modern skyscraper: here, after the Great Fire of 1871, American architecture reinvented itself, giving rise to one of the most famous skylines in the world. Its beating heart is the Loop, the business district encircled by the elevated 'L' train, where masterpieces by Louis Sullivan, Mies van der Rohe and Frank Lloyd Wright stand side by side. A short walk leads to Millennium Park, with the gleaming 'Cloud Gate' sculpture (nicknamed 'The Bean' by locals) and the Jay Pritzker Pavilion designed by Frank Gehry. Nearby, the Art Institute of Chicago, one of America's great museums, guards Impressionist masterpieces and Grant Wood's celebrated 'American Gothic'. Along the water, the Chicago Riverwalk offers another vantage on the city, while the boats of the Architecture River Cruise glide between the façades, recounting a century and a half of building ingenuity. Toward the lake, Navy Pier with its Ferris wheel and the Magnificent Mile, the elegant stretch of Michigan Avenue lined with shops and hotels, set the rhythm of city life. Yet Chicago is also music and flavour: the home of electric blues and jazz resounds in the clubs of the South Side, while its tables serve the hearty deep-dish pizza, Chicago-style hot dogs and the food markets of lively neighbourhoods such as Pilsen and West Loop. Rising to the 412-metre Skydeck of the Willis Tower, the gaze sweeps across the lake and the boundless Illinois plain. A city of lakes and skyscrapers, of jazz and bold architecture, Chicago reveals itself on foot, amid the gusts that earned it the nickname 'Windy City' and the unmistakable energy of the American Midwest.

Denver stretches out at the foot of the Rocky Mountains, exactly one mile above sea level, hence its famous nickname of the "Mile High City". Capital of Colorado, it is a dynamic, open-air metropolis, the ideal gateway to the great wild expanses of the American West, where urban energy meets a passion for nature and mountain sports. Its historic core is LoDo (Lower Downtown), a district of nineteenth-century red-brick warehouses skilfully restored and now alive with craft breweries, galleries and venues. Here stands the splendid Union Station, an elegant railway terminal transformed into a lively gathering place of cafés, restaurants and shops. Nearby, the pedestrian 16th Street Mall cuts through the commercial and financial centre, while the Colorado State Capitol, with its gold-leafed dome, dominates the Civic Center. The city boasts a notable arts scene, with the boldly designed Denver Art Museum and the creative RiNo (River North) district, a realm of street art and breweries, for Denver is considered one of America's craft-beer capitals. Culture lovers will find nearby the Red Rocks Amphitheatre, a natural amphitheatre set among towering red rock formations, among the most spectacular concert arenas in the world. Its privileged location makes Denver the perfect base from which to explore Rocky Mountain National Park, the ski resorts of Aspen and Vail, and Colorado's endless alpine landscapes. The local table reflects the frontier spirit, with grilled meats, Tex-Mex cuisine and local produce, to be paired with one of the city's countless beers. Between gleaming skyscrapers, mountain trails and more than three hundred days of sunshine a year, Denver invites you to fully embrace the adventure of the West, with one foot in the city and your gaze turned toward the peaks.

Framed by Colorado's Rocky Mountains, where the Colorado and Roaring Fork rivers meet, Glenwood Springs is a historic spa town set amid spectacular mountain scenery. Its hot waters, flowing from natural springs, feed one of the world's largest thermal pools, drawing those in search of relaxation and wellbeing for generations. Above the town, a gondola climbs to the Iron Mountain Adventure Park, while the nearby Glenwood Canyon offers scenic trails up to the striking Hanging Lake, an emerald pool suspended among the rocks. Volcanic caves, the ski slopes of renowned Aspen not far away and rafting-friendly waters round out an offering that blends adventure and rest.

Grand Junction rises in the Colorado River valley at its confluence with the Gunnison, the main city of the state's western slope. Surrounded by spectacular scenery, it is an ideal base for visiting Colorado National Monument, with its red-rock canyons, and the orchards and vineyards of the Grand Valley. The lively pedestrian downtown and thriving food-and-wine scene round out the appeal. Grand Junction is the perfect destination for those seeking desert nature, mountain wines and outdoor adventure in western Colorado.

Framed by the snow-capped peaks of the Wasatch Mountains, Salt Lake City is the capital of Utah and the spiritual heart of the Mormon community. The majestic Temple Square complex, with its granite temple and the famous Tabernacle of extraordinary acoustics, marks the orderly, light-filled historic centre. Just beyond the city stretches the Great Salt Lake, an immense expanse of briny water home to migratory birds. Its privileged location makes Salt Lake City an exceptional ski base: the renowned resorts of Park City, Alta and Snowbird, host of the 2002 Winter Olympics, lie just a few kilometres away. In summer the surrounding canyons invite hiking, mountain biking and high-altitude trekking. A young food scene and thriving craft breweries enliven a centre in full transformation. Salt Lake City blends devotion, alpine nature and outdoor living in a surprising union.

Reno spreads out at the foot of the Sierra Nevada, in the high desert of northern Nevada, and has long billed itself as "The Biggest Little City in the World." Famous for its casinos and the neon signs that light up the night, it offers a more relaxed and accessible face than nearby Las Vegas, with the Truckee River running through the revitalized Riverwalk District and a growing arts scene, heir to the creative spirit of the nearby Burning Man festival. Its location makes it an outstanding base for outdoor lovers: less than an hour away lies Lake Tahoe, an alpine jewel of turquoise waters, a paradise for skiing in winter and water sports in summer. Between gaming, mountain excursions and a lively food scene, Reno blends the energy of the lights with the wild charm of the American West.

Wrapped in the fog that drifts in from the bay and draped over steep hills facing the Pacific, San Francisco is one of America's most beloved cities, refined, rebellious and deeply cosmopolitan. Its symbol is the Golden Gate Bridge, the unmistakable red span reaching out towards the ocean, revealed and hidden by the morning mists. To walk the city is to be surprised by its rolling streets, still climbed today by the famous cable cars that scale the heights of Nob Hill and Russian Hill, offering sudden glimpses of the water. Along the Fisherman's Wharf waterfront the sea lions of Pier 39 bark and the air smells of sourdough bread and fresh crab, while offshore stands the island of Alcatraz, with its historic penitentiary reachable by boat. The charm of San Francisco lives in its neighbourhoods: the Victorian Painted Ladies around Alamo Square, the Chinese energy of Chinatown, the oldest and liveliest in America, the rainbow, activist streets of the Castro, and the bohemian ferment of Haight-Ashbury, cradle of hippie culture. At the city's core, Union Square buzzes with shopping and theatres, while the Civic Center and museums such as SFMOMA and the de Young reveal its cultured soul. Green spaces abound: the vast Golden Gate Park holds Japanese gardens, conservatories and trails down to the ocean. The dining scene is among the most innovative in the country, from fusion cuisine to the wines of the nearby Napa and Sonoma Valley and organic markets. From San Francisco it is easy to set out for California's national parks, the redwoods of Muir Woods and the Big Sur coast. Free, creative and swept by the ocean wind, San Francisco wins over anyone willing to be led by its hills and its suspended light.