SHANGHAI – Amid greetings in both Mandarin and the Shanghai dialect by a group of energetic US college students, the world's largest economy inaugurated its pavilion at Expo 2010 Shanghai on Monday.

Overcoming the challenge of a US law that prohibits public funds being used for the Expo, the country did it the hard way, relying on donations and corporate sponsorships to make sure it made a significant presence at Expo 2010 Shanghai.

"It's quite a remarkable achievement," said Jose H. Villarreal, US commissioner-general to the Expo.