A smartly dressed, flesh-tone female receptionist robot greets and directs visitors with blinks and hand gestures, fielding questions in four languages. Fuel-cell hybrid buses ferry passengers, driverless, between buildings constructed with bioplastics and reused steel, their facades enveloped by plants and cascading water for natural cooling. Diners eat rice bowls and curries using biodegradable utensils, which are composted or burned at high temperatures to feed fuel cells for on-site power.

This vision of an eco-utopia is made real at the 2005 World Expo, an international exhibition of new technologies and global culture running through Sept. 25 outside Nagoya, Japan.