JIDDA, Saudi Arabia  Just off a desert road about an hour’s drive from this port city, an enormous arched gate capped by three domes rises out of the sand like the set for a 1920s silent film fantasy. It is, instead, a fantasy of contemporary urban planning, the site of what one day will be King Abdullah Economic City, a 65-square-mile development at the edge of the Red Sea. With a projected population of two million, the city is a Middle Eastern version of the “special economic zones” that have flourished in places like China.

The city is one of four being laid out on empty desert around this country, all scheduled for completion by 2030. They follow on the heels of the country’s first coeducational university, which opened last year next to the King Abdullah site, and a financial district nearly the size of Lower Manhattan that is rising on the outskirts of the capital, Riyadh.

Architecturally they couldn’t be more dreary and conventional  bloated glass towers encircled by quaint town houses and suburban villas decorated in ersatz historical styles. Their gargantuan scale and tabula rasa approach conjure old-style Modernist planning efforts like the creation of Brasília in the 1950s or the colossal Soviet urban experiments of the 1930s, but these are driven by anxiety over the future, not utopian idealism.

With more than 13 million Saudis  half the population  under 20, the 86-year-old Saudi ruler, King Abdullah, is trying to create more than a million new jobs and 4 million homes within 10 to 15 years. He and his royal clan envision an economy less dependent on oil, run by a new class of doctors, engineers and businessmen who can function in a global marketplace.