Detail of Korean Pavilion by Mass Studies

Decades ago, long before an architect could tweet his latest design to bloggers and PR people, world’s fairs were a big deal. The World’s Columbian Exposition, held in Chicago for six months in 1893, attracted 27 million people, about half the U.S. population at the time. Any kid living in or around New York City in 1939 or 1964 no doubt begged his parents for a ticket to the two world’s fairs in Queens. But ask someone today how psyched they are for Expo 2010 in Shanghai, and you’re bound to get a blank stare. While world’s fairs have long since lost their cachet, countries are still sponsoring praiseworthy pavilions. Here are the ones we think will make the biggest splash in Shanghai.