Barajas was completed within six years of being conceived. "Arguably," said Rogers, "in the way it was run and delivered, the most exciting job of my life." The architect, who was born in Italy, is a devoted foodie — his wife, Ruth, created the swish River Café (and wrote the cookbooks featuring its refined Italian cuisine), which is conveniently next to his offices. "I'm a great believer in food as a good way of sparking ideas. In Spain we ate very well, we drank, we went out at night, but they get the work done."

In contrast, his new British Airways Terminal 5 at Heathrow, which opens this spring, took 20 years to build. What architects call the "client body" was 450 people strong in London, every one of them with an opinion; in Madrid, it was 20.

That, I thought, could be one reason architects love working in Spain.

I've been visiting Spain since 1958, when I drove there from London to see a building then only vaguely heeded in northern Europe, the cathedral in Barcelona known as La Sagrada Familia, by an architect thought by some to be deranged and by others a genius, Antoni Gaudí. He died in 1926, leaving incomplete drawings of his cathedral, and by 1958, with Spain living in the stasis of the Franco regime, resources were scarce and the work had not progressed very far from how it looked in a 1900 postcard that I found. At the hot, dusty site on the Carrer Provença, only a few masons labored away behind a high fence. The cathedral was little more than a facade, but what a facade! I looked and looked at the four spires shaped like slender rockets, their surfaces pitted and barnacled and dripping in a decorative scrim of stone. A keen amateur student of architecture, I felt I had been punched in the eyes and forced to rethink what architecture was — and could be.

Gaudí smashed the mold. He was certainly odd, but visionary, too: His last secular building, the apartment block called Casa Mila — finished in 1910, in the infancy of the automobile — included an underground parking garage. In a real sense, no architect working in Spain today can be immune to the presence of Gaudí's astonishing imagination.

Rick Lew / Conde Nast Traveler Almond biscuits, a Sevillian specialty, are sold in this early 20th-century gem called La Adriática (or Edificio Filella, for the buscuit maker), on Avenida de la Constitución.

In the 1970s, when Spain sprang free, more or less overnight, from Franco's repressive 36-year grip, there was a surge of creative energy that could not be matched elsewhere in Europe — not even in those countries later blessed by release from communism. After I had traveled from southern Andalusia to the northern Atlantic coast and had seen works finished, works in progress, and works being conceived, it struck me that the Spanish have been able to do more within a couple of decades of rejoining the rest of Europe to advance the drama of their landscapes than would be possible in a country with an infrastructure put in place much earlier — not to mention one with a conservative bent for valuing the past more than the future, or with the complacency that comes from giving the world 2,000 years of classic building styles. (Think Italy.)

Right now, nowhere else in Europe has such visually rewarding travel. For example, the new highways that link the northwestern province of Galicia with Madrid involved boring tunnels through mountains and building long viaducts across valleys. This has been achieved with something more than engineering — there is a visual panache to these works, a verve that goes beyond what is required simply for function. I drove over a succession of bridges in the northwest, some of them spanning little more than streams, that were individually distinct and collectively a symphony of bridge-making art. Any country that cares that much about how one small bridge fits into a landscape shows the same love of detail that the Romans insisted upon in feats like the magnificent Pont du Gard aqueduct in southern France — a structure that's so much more than just a channel for carrying water 31 miles for the public baths in Nîmes. That's the thing about good architecture: It leaves a reputation that can last a couple of thousand years.

Rick Lew / Conde Nast Traveler High-strung: WIth daring simplicity, the single pylon of Calatrava's harplike Alamillo Bridge, in Seville, supports the 650-foot span.

Seville, the landlocked capital of Andalusia, is a real test of whether a surge of modern building can sit well in a city with a fragile, storied past. I was last there a year before it staged the 1992 World Expo, and worried in a grumpy way that it might be too hell-bent in pursuit of the new. (The urge for renewal is more easily understood when you discover that, thanks to Franco, as late as 1982, Andalusia had not one functioning theater or orchestra.) As it worked out, the Expo left three notable landmarks: the Alamillo Bridge, by Santiago Calatrava, supported by its single, sharply angled pylon like the upended frame of a harp; the Santa Justa railroad station, a truly inspired updating of the Victorian vaulted shed, by Antonio Cruz and Antonio Ortiz; and an airport terminal by Rafael Moneo that, to this day, is a pleasure to pass through. None of these damaged the city's character.

The old core of Seville was shaped by the Arabs from 710 to 1248; Moorish architecture went with what was, by the tenth century, city planning of a very advanced order. Simple and effective climate control, conceived in the desert, came to urban living in the form of many inner courtyards where fountains were used to convect warm air upward and cool air downward for human comfort. You could have hoped that the Arab street plan, with as many twists as a souk, would defeat the car. But by 1991, I could already see that the local drivers had an insouciance able to make the most formidable obstructions seem malleable. And by the beginning of this century, cars were infesting every alley.

Rick Lew / Conde Nast Traveler On the town: Seville's core, built between 710 and 1248 by the Arabs, was a model of urban arts. In 2006, the citizens voted to ban cars, reclaiming the ancient streets.

Seville was already a thriving urban center when Caesar arrived in 45 B.C. "You can't dig anywhere in this city and not find something old," said Emilio Carrillo, the deputy mayor whose remit is to shape Seville's future without further harming its extensive past, a trick that European planners never find easy. We spoke in an airless office on an island in the middle of the Guadalquivir River, a relic of the Expo site. Carrillo knows what is at stake — he's also a professor of history, as comfortable with Roman chronicles as with the grand urban scheme that he now directs, funded to the tune of $4 billion.

When we met, he had a big victory behind him. Seventy-six percent of the citizens had voted for a new plan that would, in effect, remove cars from a large part of the old city. On one condition: that a new tramway would circle the city core to make pedestrian access much easier — as historic centers go, Seville's is enormous, three square miles. The tramway, built in a year, will be a boon not simply to the more than 700,000 residents of Seville but also to the 2.2 million visitors who come each year — as will the 40 new hotels planned (many converted from convents). A high-speed rail line already brings Seville within two-and-a-half hours of Madrid, and a new line is being built from the city to the Mediterranean playground of Malaga, 90 miles away — a journey that will take just over an hour instead of three.

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