When the organizers of New York's 2012 Olympic bid were forced to reimagine their stadium, they moved it to a new borough and cut its lifespan.
The stadium that had been proposed for Manhattan's Far West Side would have remained essentially as it was built, a behemoth that was to house the Jets. But the stadium proposed for Queens will take Olympic form for less than a year before reverting to a smaller park for the Mets.
On the surface, such a conversion works perfectly with the International Olympic Committee's "no white elephants" pledge. Because so many of its host cities are burdened with large stadiums that are largely unusable, the I.O.C. has pushed cities to plan useful afterlives for their facilities.
"These buildings have got to have a legacy," said Rod Sheard, an architect for HOK Sport in London, who has worked on the design for the proposed stadium for London's 2012 bid. "The Olympics need to protect their event, and it's got to be a spectacular event, but in the end, it's only two weeks."
I.O.C. leadership appears committed to that concept, but the 116-member I.O.C. does not change direction easily. After decades of seeing palatial Olympic shrines built, I.O.C. members may be slow to embrace a new era of design.
When the I.O.C. selects New York, Paris, London, Madrid or Moscow as the host city for the 2012 Games on July 6, voters will also be making a choice between two eras of stadium design.
Paris comes ready-made with Stade de France, a 71,000-seat sports palace built in 1998 for large events. Madrid and Moscow plan to renovate stadiums; Moscow would renovate the centerpiece from the 1980 Games.
London's stadium would be built to Games scale, then converted to a permanent 25,000-seat facility for track and field. New York's stadium in Queens would start as a 54,000-seat home for the Mets, be expanded to 80,000 seats for the Olympics, then revert to its ballpark size.
"When you have a choice of going to one of the greatest stadiums in the world in Paris or choosing something that's temporary, I don't know how they're going to view that," said Ron Turner of Turner-Meis architects.
Turner's skepticism stems from his work on the stadium in Atlanta for the 1996 Games. He said the I.O.C. turned down his firm's initial idea to use steel, which could be removed and used afterward to build a football stadium to be shared by Atlanta's three historically black colleges.
"It would have cost a lot less, and you would have gotten a college stadium out of it as well," he said. "It seemed like a great idea to use the material again."
Instead, the Olympic stadium was built with concrete, and a portion of it was torn down after the Games to convert it into Turner Field, the home of the Atlanta Braves.
Dr. Jacques Rogge, the I.O.C. president, has declared that era over. In 2003, the I.O.C. accepted the conclusions of the Olympic Games Study Commission, which recommended using existing facilities when possible, building only what can be used afterward and embracing temporary solutions.
"Of the 117 measures of the Games Study Commission, we implemented 30 percent of them in Athens, there will be improvement in Torino and Beijing, and ultimately they will be adopted by 2012," Rogge said in a telephone interview this week. "This will stop the inflation of the Games and stop the spiraling costs."
Beijing, however, designed its stadium to be grand and permanent; it will be part of an Olympic park on the outskirts of the city. It is the same kind of park that Sydney, Australia, has found so difficult to maintain and that Athens has little idea what to do with. The Australian government, for example, pays $34 million a year for upkeep of the site in Homebush Bay, a suburb of Sydney.
"From an Olympic standpoint and as a visual legacy, it's really cool," Paris Rutherford, an architect for RTKL, which was involved in the design for the Beijing Games, said of Homebush Bay. "As an economic legacy, it's not. It just sits out there, and it's like a cultural museum now."
Sydney built the largest Olympic stadium, at 110,000 seats. After the 2000 Games, capacity was cut to 80,000, a renovation that cost $100 million.
Rutherford argues that the ideal was the Los Angeles Olympics in 1984. It was the first Games to turn a profit, but its lessons have not stuck.
"That was a careful reuse of existing facilities," he said. "It was based on creative logistics, not new construction."
Now, Olympic planners find themselves in a complex age. Stadiums are expected not only to hold events, but also to rejuvenate parts of cities. Architects must envision a structure that is grand enough for Olympic pageantry, neighborhood-friendly enough to gain acceptance and flexible enough to have a post-Olympics purpose.
"I was a bit sad to see New York didn't get approval for the West Side," Sheard, of HOK, said. "I think it would have been a great boost to the city."
Instead, New York was pushed into the conversion age.