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.

In the 1970s, when Spain sprang free, more or less overnight, from Franco's repressive thirty-six-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 two thousand 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 thirty-one 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.