The largest world's fair ever held, and the first in a developing nation, closed on Oct. 31 in Shanghai, China. The favorite topic of conversation for the true expo nerd? Where's the next one?

There are two short answers to that. In 2012, our Pacific Rim neighbor South Korea will host a three-month, specialized expo in the seaport of Yeosu with a focus on coastal issues, a topic of great relevance here in the Northwest. The next universal expo, the big, six-month kind like Shanghai, is slated for Milan, Italy in 2015. Expos are ephemeral and forward-looking, and the traditional closing ceremony ends up with a symbolic hand-off from one country to another. In a kind of recapitulation of the culture exchange between Marco Polo and the Orient, the Chinese concluded their fair by handing an exposition flag to a representative of the next host of an equivalent-sized event, the mayor of Milan.

The Italian fair is already generating buzz. The theme is feeding the planet. Who'd want to miss a fair about food in Italy?

But there are also some intriguing prospects a little further out and closer to home. We could have an expo on the West Coast along the southern Bay Area border of Ecotopia in 2020, or even sooner, in the northern reaches of the Cascadia economic zone, namely Edmonton, Alberta. 

The last true Pacific Northwest fair, and the last in North America, was in Vancouver, B.C. in 1986. That expo brought lasting changes to the city, ones that set the stage for the hosting of the Olympics and the continued evolution of False Creek as a cornerstone of the "Vancouver miracle" combining urban growth and sustainability. The impact of expos can be significant for regional cities, but also larger regions.

Century 21 in Seattle in 1962 was a boon for tourism, bringing millions of dollars to the Northwest by appealing to suburban car-campers. The result was a kind of grand-tour by station wagon as moms, dads and their baby boomer kids flocked to see Mount Rainier, Victoria, Crater Lake, even Yellowstone, enroute to the Space Needle.

So, close-in expos can snag tourists, promote regional trade, and gain visibility even for those not at the center of things. Nearby states, for example, might have their own pavilions, as Washington has had at earlier expos in San Francisco, San Diego, and Vancouver, to name a few. Expo city bidders can actually influence the trade agenda, and certainly Northwest-based corporations will be prime targets for expo sponsorships, from Microsoft and Amazon to Starbucks, Boeing and Nike.

Sparked by his visit to the Shanghai Expo in September, California's Arnold Schwarzenegger announced that the Silicon Valley would bid for an expo in 2020. The idea is backed by the business group, the Bay Area Business Council, whose members consist of the 275 largest employers in the region, including Yahoo, Google, Apple, Hewlett-Packard, Chevron, and Wells Fargo. Members are reported to be very supportive of the concept. 

A Silicon Valley bid is intriguing for many reasons; one is that no expo has been held in the U.S. since 1984 (New Orleans), and the last in San Francisco was on Treasure Island in 1939-40, so it could be argued that one is overdue. Second, the Silicon Valley concept comes with a specific piece of land in mind, 800 acres of Moffett Field in Sunnyvale between San Francisco and San Jose. The idea is to transform the former Naval Air station, once known for its airships, into a into higher education facility for the University of California, expand the Google campus, which shares the site, and allow NASA to develop a new high-tech campus. NASA already has facilities there.

It is difficult for mature cities to find enough exposition space unless, like the Chinese, you are willing to use bulldozers freely. But Moffett Field is a tempting, developable site along major highway and rail lines. A hub for cross-Bay ferry service is already slated to open there in 2020. If expos are nothing else, they are globally attractive local urban redevelopment projects.

While expos invite the world, the legacy they leave behind is usually very local. Without a local goal, and the willingness to spend state, county and city money on new infrastructure and support, they are DOA. Too, they require deep pockets and support in the business community. The Silicon Valley bid alone will cost around $8 million, according to early estimates. The bid process is not for those who aren't serious.

The bad news is that California is struggling financially. The good news is that there is a major opportunity right in the middle of an economic zone (the Silicon Valley) which is on high-tech's cutting edge. The theme isn't set in stone but is coming into focus, emphasizing sustainability, innovation, and space (doesn't every high-tech entrepreneur have his own spaceship company these days?). The valley has big corporate resources who could help fund a fair, that is, if they don't see expos as old hat. 

A frequent suggestion is: Why aren't expos just done online? One reason is they are about the real world, especially real estate. As long as people need office parks, housing, bridges, trains and subways, highway improvements, and sewer systems, expos will be a way to leverage resources to accomplish the mundane with an inspiring, utopian gloss. An iPod or Xbox expo era is not in the offing. Another reason: Expos are great consumer showcases for cutting edge technology, like 4-D multimedia, better than digital devices can offer. Plus, lots of people still come to world's fairs.

Shanghai hosted over 73 million people, a record (even if some attendance was state mandated). No one expects numbers like that in the jaded, media saturated USA, but still, tens of millions of people turn out for these events.

A major hurdle for the Silicon Valley effort: to bid and host, the U.S. would have to rejoin the Bureau of International Expositions (BIE), the Paris-based organization that oversees expos. The U.S. dropped out during the George W. Bush era. I was recently a guest of the BIE's in Shanghai, and getting back in good standing might be complicated for the U.S. It would require about $300,000 in back, current, and future dues to get through the bidding process for 2020, but it also might (or might not) require an act of Congress. 

John Grubb, senior vice president for external affairs for the Bay Area Council, says they have a strategy for resolving the BIE issue. It has several prongs. One is to pass legislation, during the lame duck session of Congress if need be, to lift federal prohibitions limiting U.S. involvement in world's fairs. That isn't required for the bid, but it signals that the U.S. is prepared to take seriously the expo movement, whether we host a fair here or not, and it opens the possibility of future federal support for pavilions here and abroad.

A possible helper in this process: the freshly re-elected Sen. Barbara Boxer, who serves on the Senate Foreign Relations Committee. Second, the Silicon bidders are offering to pay with private funds the BIE dues so no federal appropriation would be required. They hope their plan will be a bipartisan effort: Another city very interested in an Expo in 2020 is Houston, and Texas Gov. Rick Perry, a Republican, is reportedly an expo enthusiast.