Aichi Expo 2005, which opened Friday, differs significantly from previous world expositions. Its theme, "Nature's Wisdom," is the reason why. The six-month fair embodies two overarching principles: environmental friendliness and civic participation. The original construction plan was criticized for its possible impact on the environment, prompting organizers to select a more eco-friendly design.

Aichi Expo demonstrates how far Japan has come in dealing with environmental issues. Thirty-five years ago, in 1970, Japan hosted its first world exposition in Osaka under the theme "Human Progress and Harmony." It was a landmark year in which Japanese citizens, including local administrations, began thinking seriously about how to balance economic development and environmental conservation. Aichi Expo, with its emphasis on nature, is also a tribute to the Kyoto Protocol on climate change, which took effect earlier this year.

The Nagoya City Pavilion, located at the center of the fairgrounds, features a dome that seems to symbolize Mother Nature. It is called "Daichi no Tou" (Tower of the Earth), a brown, modest-looking structure that sets itself apart from Osaka Expo's gorgeous "Taiyo no Tou" (Tower of the Sun).